First, join competitions. That'll give you a some structure to work with. An Artstation competition just started; go join that. Second, get people to hold you accountable. Doesn't have to be another artist, just tell one of your friends to shame you if you don't hit your deadlines. If that doesn't work, tell the friend…
Now if you're not comfortable going it alone then as touched on previously, try joining a team activity be it an online modding project/indie...something-or-rather or even find/get together with a local group of like minded people interested in 3D CG/Game dev stuff...etc, etc. If nothing else you'd essentially be…
What did it for me, was quitting stuff that were my biggest distractions. So I basically asked Steam to remove my 3 most played games from account, since then I've found myself doing a lot more than i used to before. Of course, you can never fully escape procratination but it's about reducing it. Personal tips that a lot…