Drawing and painting practise

I'm very keen to develop my drawing and painting skills and would especially like to work on different ways of portraying people. I loved the work of Minna Havas - see previous post and want to try both making my figures more realistic and also being more abstract. I've posted below some illustrations I've produced.
The first one is of some good friends - I tried using coloured pencils as per Minna Havas. I think it works to an extent although is by no means anywhere near as realistic as the work of Minna.