Okay, well, six months into editing my accursed-unending-little *ahem* beloved work, I have found it more than a little important to put together a list of all the tips and tactics I've used to stay interested. I think inspiration is important at all times of the writing process. I don't mean the flash-of-inspiration-that-will-end-all-worries that some would-be writers spend their lives waiting for. No, I mean that vague, generalised sense of interest, curiosity, and perhaps passion that suddenly makes it not seem so bad to sit down and work. So without further ado, this is what I do:
Watch Movie Trailers. I dunno. I think it's all the bright lights, loud music, and interesting quotes thrown together in the space of a few minutes. A good trailer is unlikely to help me nut out just what Jason SHOULD say to Lirrian, but it does help get me in the creative mood. Besides, it provides inspiration for what movies should be on my To-Watch list.
Cinema Visits. Watching movies at home is okay for a bit of a creativity enhancer, but it's the loud noise, dim lights, and sheer ambience of a cinema that works the most for me. Again, I rarely get a flash of inspiration on how to resolve a plot issue from watching movies but it does get the creative juices flowing.
Exercise. Not so much the slow grind down at the gym, but rather going for long, brisks walks, running around the block, dance lessons, or doing silly things like chasey and stuck-in-the-mud. In case you're wondering, I'm 25. No, really. I think it's the adrenaline coupled with the time to think. This actually can help me work out plot issues.
Daydreaming. I only do this when I'm already excited about what I'm writing, but it does bear mentioning anyway. Forced daydreaming while listening to inspiring music can also help.
There are other things that might work for you though they don't work much for me. Reading novels helps me hone my craft but doesn't tend to leave me excited to write my own works. Some might enjoy cooking for the same reason why I enjoy exercise. Others might do a spot of guided meditation or visualisation.
Oh yeah, if I ever get published, remind me to declare that I require a weekly hour-long massage to keep my creative juices flowing...