Its great to see you doing these paintings as its clear you love the process of creating them. I'm not huge on abstract stuff, but perhaps thats because I have not yet explored it myself!
If you really want to get better at drawing from life, and painting realistic things, perhaps you should put a bit less time into the abstract for a while...it all comes down to what your goals are and what will make you happy, and if thats abstract so be it! I would like to see more longer life studies, as they should benifit all aspects of your art. Keep doing those basic head studies and then do a self portrait to challenge yourself and apply the knowledge see you