I make playlists on youtube of music for specific books so that when I need to get in the mood or start writing I have that as background music to motivate me and keep me writing, plus it keeps me focused.
Also, a lot of times I’ll make myself a cup of spearmint tea. The smell gets me into that creative mood, and it’s good for me. Plus, I can’t say this is completely true, but I think some research suggests that herbal teas can stimulate your mind.
If I’m really in a rut, I might go for a walk and simply think about my story to generate interest. Or I’ll remind myself that I’m only doing a little bit.
I have my writing broken up into 5 15-20 minute sessions or 5 one page sessions where I sit down and write at least one page in that sitting, and I try to ensure that I do a minimum of 3 a day but I aim to get 5 done, that way at the end of the week I’ve completed between 21 and 35 pages, and because it’s shorter bursts of writing, I can motivate myself to do it easier because it’s not some giant looming task. Also it allows me to think in between pages so if I get stuck on something or need to look something up, I have time.