Digital's a big step! -well, digital on-screen is big. Wacom tablet as mouse was manageable for me since I'm from pen(cil)+paper land.
As for guides? Uh, hmm. A sure bet would be studying light and shadows and try to have your lines comply with those rules.
join us.. dive in.. the lava's fine XD
My .obj format 3d models
for learning blender3d.