Hey Alex, so sorry mate, just looking back through the threads and realised I didn’t leave a reply to your question. Hey definitely a decent attempt at freehand work. The first thing I can notice is the paint was way too thick on application, as with all painting you should build up a lot of thin layers instead of going in with thick coats to get the coverage.
So to get a really great look you have to blend the colours into shades and up to the highlights to give it that realistic feel.
Freehand is really just classical painting in 2D, although at a really small scale which makes it a bit more difficult. I would say if this is something you would like to master, just do a lot of practice, not necessarily on minis, just on a piece of paper, or even better prime a ice cream container lid etc so you can work on a medium which will be the same as the surface of a mini.
As for sketching onto a mini, I normally outline it in with a rather thin ink first as to not leave any brush strokes or texture, and this can be easily painted over if the lines aren’t too straight to start with.
Anyways mate, just keep practicing and you will learn a little more every time you try. Keep up the good work.