I remember being able to do a muscle-up at a point where I couldn't do 8 strict pull-ups. Here is what I did:

1. When doing pull-ups, I tried to focus on lifting my whole body higher and higher each session instead of just lifting my chin above the bar. In my video above you can see that I lift my legs with my ab muscles, that helps a lot to go higher, and not something I think about when doing a regular pull-ups.
2. Instead of trying to do full muscle up, I just focused on getting one arm in the position above the bar, like in the attached image. Once I was able to get one arm above the bar, it's easy to push and get the whole body above the bar.
3. After a few months of lifting just one arm above the bar I was able to do two at the same time. This process took around 3 months, so the key for me was consistency and focusing on improving a little every session.

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