/ic/ - Artwork/Critique

This must have been asked a ton of times (a few ones in this thread only) but still.
I'm a guy who used to draw during classes in school but nothing more, ever. So I'd like to start drawing seriously on my spare time and I'm looking for some exerices I can grind for a few months every day to get some basics.
The only thing I used to do, is copy some characters from Mangas I used to read and got so used of drawing some of them that I ended being able to "mix" everything up and draw specific poses/faces/eyes from memory.
Now I'd like to picture a pose in my mind and draw original designs. I opened Krita today and did this from this mannequin I have on my desk.
Should I keep doing this? Anything else I can do an hour or two a day everyday before doing my own thing?