I like watching other people paint on youtube, or seeing others work on instagram, my game stores group, etc. They're a lot better than me, but it's something I can work up to. I think of it like watching a guy bench 4 plates, both serve as inspiration.
For motivation, it comes and goes for me. I've found that the more I immerse myself in 40k, the more I want to paint or game. Audiobooks are perfect for that. I watch batreps, too, and I'll see the board full of painted models and think "I want that to be me next time I get a game in".