How To Keep Your Android Tablet/Phone Fast

Please note that this article may be subject to major updates including new content and tips being included in the very near future. 

I was recently given a new tablet as a very late birthday present after my old tablet broke. This new tablet is a Nexus 7 and my first concern has been ensuring that the Quad-Core Tegra 3 processor remains lightening fast for as long as possible. 

I thought I'd write up on some of the simplest, but also best, ways to make sure your tablet (or phone) stays fast and smooth too. Enjoy!
Dealing With Google Currents
If you are finding that your tablet (especially the Nexus 7) or phone is suffering slow downs and lag, then you might want to try dealing with Google Currents. 
The app is well known to cause stuttering and lag on the Nexus 7, however some other mobile devices can also have this issue too, especially after the Android 4.2.2 update.
There are two ways to deal with Currents, one of which reduces lag and one that pretty much gets rid of all of it.
Way 1:
1) Go onto the Google Currents App.2) Go into App settings. This can be accessed by taping the android menu button (3 dots together).3) Uncheck the Enable Background Sync option.4) Restart your device.
After this the lag should be much reduced, however if you are still having problems with it simply go ahead with Way number 2 and disable the Currents app completely. Simply go into the App section on Settings, select Currents and click Disable. Agree to all the little boxes that come up notifying you that the app will basically uninstall and then it will go ahead and remove it from the device. If you want it back at all just go into the Play Store, go onto the Currents app and click 'Enable'. 
After disabling all lag should be gone. 

Avoid Side Loading Apps, Movies, Music etc.

I know that one of the awesome things about Android is the ability to side load apps, however this isn't actually good for your device. While saving yourself a few pounds/dollars for a game or app, or downloading some music or TV programmes and movies through the Torrent app you can get might seem like one of the highlights of your Android device, you do all this at your device's performance expense.
Side loading media is one of the easiest ways to clog up your device and make it slower. Downloading all your shit through Google Play or Amazon or an actual registered service is always smoother because these services are designed for your tablet/phone. When you download from the internet you are downloading from something that is simply compatible with your device, no actually built for it. There are tons of reasons that side loading content is far from good for your device.
If you simply want to download a couple of apps here and there then knock yourself out, but if you intend to go to town on the whole side loading business, then do so at your own risk. Android may offer you this ability, but it doesn't necessarily mean that it is good to use it.

Manage Your Widgets

This is yet another piece of advice that is no doubt going to cause upset to any Android users reading, however luckily it isn't actually that big of a deal.
Widgets. They're one of the unique things that Android offers that Apple doesn't. And people love them. Unfortunately widgets also have a dark side; they clog up your home screens and slow your device down when navigating the UI. 
Just like having a Live Wallpaper slows your device down (this is common knowledge so I didn't think I'd mention it in its own section) widgets also tend to clog up your device too.
Having all of your home screens filled to the brim with widgets won't always make your device too laggy or slow, however it won't make it buttery smooth either. Widgets aren't a big deal, however if you really want to ensure navigating the UI is smooth and easy, then I wouldn't go to town on the Widgets. Just have a couple on each screen and you'll be fine.

Avoid Apps With Push Ads

Everyone knows and generally agrees that ads are a pain. They interrupt your favorite TV programmes, force you to watch them before even the shortest of Youtube videos and take over websites to the point where you don't even know if what you are clicking is an ad or an actual part of the website itself.
However ads on Android are probably the biggest bum. While having them pop up during a game is irritating enough, push ads are beyond infuriating, especially as - and this is really relevant if you download a lot of apps - it can be hard to identify exactly WHAT app is supporting these damn ads.
Avoiding apps that support push ads is really essential in making sure your device stays speedy because push ads slow down your Android tablet/phone like crazy.
In case you are unsure about what push ads are exactly then let me bring you up to speed.
Push ads are basically ads that force their way onto your device. Instead of appearing ONLY when you are in the app itself, they appear randomly as notifications in your notifications bar, they can appear as bookmarks in your browser and they can even become actual shortcuts on your Android's home screen.
While the latter two can be dealt with by simply deleting them, the first form of push ad - the one that appears as a notification - is constant and can only be stopped by actually uninstalling the app itself.
Push ads are just horrible, horrible things and they can ruin good apps. A lot of the time they are used in apps that you will not access as much. So unlike a game, which you will likely start up and play more frequently, apps that support push ads are often ones that are less often used, like an internet signal booster or a type of widget app. Because you don't use these as much, the developers will not get anywhere near the amount of money from in app ads that they would if they had developed an app that you would actually directly use more. So they put in push ads instead, which infiltrate your device and cause you to rip your hair out in frustration. However the developers are still smiling because they're getting their money.
Anyway, if you want to keep your device, especially the UI, as smooth as possible as well as avoid the total infuriting-ness that is notification ads, then avoid, at all costs, push ad apps.
Unfortunately, despite the fact that Google Play has some rules regarding this form of advertising, these are either ignored or sneakily got around, and it can be hard to identify if an app is actually going to spam you with ads or not. Some tell you if they will, others do not.
Best way to avoid push ad apps is to simply read, very carefully, the description of the app before downloading. Also, try not to download too many apps all at once otherwise you might lose track of them and not realize which one is ad-ing you to death.
Another tip is to avoid fake and/or stupid apps. Things like 'internet boosters' and 'performance improvers' and silly apps like 'fart noises' tend to be the most common push ad culprits, so keep your wits about you and download sensibly.

Remember To Clear Your Cache

Pretty basic step this but one worth noting. If you find your device is stuttering a bit or something then go into Settings and Storage and clear your device's cache. This will likely fix any issues you are having with particular apps too, especially the browser.

Avoid Custom Firmwares & Dodgy Shit

Rooting your device is fine. In fact rooting, if anything, actually improves your device's performance. However in my experience custom firmwares and special 'device altering' downloads are to be avoided. Having downloaded custom firmwares and updates on my first tablet I found out that while they can often make your device do cool things, they can also screw you over.
Custom firmwares do little except clog up your device and damage it. My advice is root your device and then download things compatible with your root, however don't just download custom firmwares and shit like that because otherwise you will pay the price.

Keep On Top Of Your Active & Running Apps & Services

If you want to ensure your device stays consistently smooth all the time, them make sure you close apps and stop services if you are not using them. Don't let the amount of active apps you have build up and make sure you close any you are not using. 
If you want to really control what apps and services are using up processing power go into Settings and then Apps and swipe along to Running. This will give you a clear view of almost all the apps and services that your device is running and how much memory and power they're using up. Select ones you are not using or want to stop and tap Stop. Sometimes a little message will appear telling you that if you stop the app/service then it or other apps/services relating to it may misbehave or stop functioning, however this is not a big deal and you can ignore it and go ahead and stop the app/service. Most of the time this message only appears when you try to stop apps/services that relate to widgets as they are always active on your home screen so they can't technically ever be stopped from running.
I hope this little tips guide helped you out and maybe resolved some issues you were having too. If you have anything, anything at all, to add, then do so in the comments! Peace.