I think your definetly off to a great start and have a lot of potential~!
As far as advice goes im not the best so hopefully these words mean something XD
for one try to make your lines thinner. A lot like in an anime, keep the lines soft but have just enough thickness so you can see them ( ^ω^ ) as for the coloring, try to use softer colors so they look better at shading.
Speaking of which, shading~! Shading is your best friend. It gives depth to an object! For shading, try to remember your light source and where the light is coming from. Also remember to shade on places that clothes overlap, somewhere where shadows are covering the object, etc. for shading colors, you can actually use palletts you fin online such as this one i find really helpful:
I think your doing a great job so far though! Good luck~!