My little one has no problem with flipping. But I do know of mums who are very worried when their little one is a little behind schedule. So here's some tips and tricks I use to help my baby flip faster (and safely).
As a first-time, I was initially very hesitant in flipping him over to do tummy-time. When my baby was a newborn, he was so soft and it was very scary to do so. We started his tummy-time on my chest. We would hug-carry him while I slowly lower my body down. Initially, he couldn't really lift his head very long.
After his 2nd month developmental check, the PD advised to start him on his tummy-time. That was when I started to flip him over. Initially, we only used a tummy-pillow and did tummy-time on the mattress as it was softer. For mummies who are not familiar with a tummy pillow, it is a U-shaped cushion that helps to soften the blow when baby slams its head down (when their neck isn't strong enough yet). We used Taf Toys 2-in-1 Tummy Time Pillow ($35.90) which had 2 different heights. (Note: My baby was quite advanced by then so we placed him on the bigger pillow.)
First-time mummies would pretty much agree that the first lift of the head is pretty much an exciting milestone. One trick I learnt to take nice photos of it is to use a Tummy Time book ($33.90). To take a frontal view photo, I would place the book in front of him so that my baby would stare at it. I will quickly position my phone in between them to take "that shot" :P
Don't worry that this will be a white elephant. We use the Tummy Time book even for his bedtime story. We definitely flip it more than once every week, quite a good mileage if you ask me. The pages make a crinkly sound and by 4-5months, our baby adored such sounds. I would pass him the book to distract him while he is on his bouncer so that I can do my other chores when it is only just me and him. The different pages also have textures and flips so you can also use it to train your child's motor skills.
As he became better with his neck control, we also started the use of a playmat. We are using Marcus & Marcus reversible playmat - ABC ($49.90) and it is huge! It can definitely fit snuggly into a playpen. For now, we are folding it so that it is twice as thick. Our little one is starting to dry-crawl, once he can really crawl, we will open the mat fully.
On one side, the design is ABC and the other side is 123. Sometimes, we do use the mat to expose him his ABCs and 123s. The design of the neutral ABCs fit our scandenavian house theme better. The colourful 123s capture our baby's eyes more. To balance it out, we flip it as and when to balance Mummy's love for aesthetics and baby's love for development. :P
Here's a photo of our complete gear! I have to say I am rather enjoying motherhood and preparing for my child's each developmental stage. Hope my tips and tricks works for you too!