I don't think that's particularly bad? Given you're clearly not lighting or composing an image for anything other than practising colour grading.
But it doesn't help that you're not lighting the face particularly well. In all but the last shot, there are significant shadows over your eyes. If you want more contrast, light the scene with more contrast as well. You can also mask and track certain areas of your footage, if you want to grade them seperately. So you could track your eyes and colour them a little bluer in post (this is obviously time consuming, so you'd only do this if there was a good reason to do so).
Colouring is the final step in the image process, generally, and as per the saying used here often, GIGO. You need a well lit, well composed, white balanced (which none of these seem to be - unless you coloured them that way?) image in the first place to actually create a pleasing image. If not, the very best you'll be doing is making your image less bad. If you want to practice colour grading, you could ask to practice with someone elses footage (that has been shot a lot better than this), or you need to take the time to shoot a better (and flatter) image to practice with. Given that, is being a colourist what you really want to do? I thought you wanted to act/direct? (not that it's bad to learn other things..)
note: I'm not a colourist or a cinematographer.