The Not So Successful Side Hustle

It took me a long time to get started. You know how you have good intentions but that box of "sell online" items sits in your closet for months because you are not sure how the shipping works and you are too lazy/scared/unmotivated to find out what to do? That is what I did. I purged, I segregated, the box sat in the closet. Finally, I looked up shipping procedures, got flat rate boxes from the PO and started taking photos of things. But then, I was not sure how much to charge and I waited again, pondering. Finally I put my first item on eBay. 
And then...nothing happened. Nothing happened for a long, long time. This was my first time and I had no idea what to expect or what to do if nothing happened, so I let it refresh (it does this every 30 days) for a long time before I finally took the listing down. Then, about six months later, I decided to try again. This time I put several listings up and I decreased the price if they did not sell after a certain time period. For a long time, nothing happened. 
And then...someone bought something! Hurray! Then I muddled through printing a label and putting it in the right box and getting it to the post office, but I did it. In the end, it was not that hard. I don't know why I waited so long to start. After that, I enthusiastically posted a half dozen other items, and...nothing happened. 
You can see where this is going! However, after about a year and a half of listing items, I have sold probably five items. So clearly I am not going to quit my day job! However, it is very satisfying to get even $20.00 for an item that I paid a lot for, as the alternative is to get nothing! HOWEVER, I do not think that the buck is worth the bang unless you are at home full time and you have free time. Let's say I probably spent five hours collecting, photographing and posting listings (and revising) and I have made....drumroll please...about $70.00. This puts me at $14.00 per hour, which is less than the $18.07 minimum wage in San Francisco. Bottom line: I should probably go get a job at a coffeeshop and give all the items to Goodwill! 
When the items do not sell on eBay, I send them to thredUp, which is an online consignment store. I have sent about 12 items to them and made $64.00, so my per hour on this is probably about $18.00-$20.00 per hour, but my per item is only $5.00 vs about $14.00 per item on eBay. I did look into taking my things to a local consignment shop but they are VERY picky, i.e. it has to be current season, certain brands etc. and most of my things are not current season (they are classics!) 
Next up is a big Goodwill/Salvation Army run, or maybe I can try one more platform, but first... 
I need advice! Have you ever sold things online? If so, what platform do you use and how successful have you been? If you have been successful, what tips can you give me? Has anyone tried or had luck with Facebook Marketplace? If so, do you let people come to your house or do you meet them somewhere? How exactly does that work!?