It is so easy to get stuck on a painting. Not stuck in a good way but completely paralyzed and unable to finish. With myself I find I am so scared that I am going to make a mistake that each brush stroke feels like it could potentially wreck hours and hours of work. That is the perfectionist in me and is why I had to give watercolour away for so many years. Acrylics were a revelation- you could paint over your whoopsies.
Now I have found the solution to the procrastination. Have more than one project on the go. That way when you feel yourself making excuses for not working (or stressing when you are) you can just move onto something else. At the moment I have an oil painting of a nude, a pen and ink logo and several cat brooches on the go. During the day I will switch from one to the other when I feel myself becoming stale and starting to sigh more than usual.
Another way to freshen your outlook is to try something completely different. Maybe a new media, a new technique, a subject you've never tried before. Recently for me it has been collage. I always associated this art form with bad school projects but now I see it as having a wealth of possibilities. In this exercise I drew one of my teapots in charcoal before photocopying it twice and using these templates as bases for collages. In this one I have ripped up some of that boring old junk mail we get every week as it had the nice glossy surface I wanted. The original teapot was royal blue but in this picture I have changed it to a comfortable brown but still retained its shadows and highlights. The only disadvantage with collage is that it takes ages to do as each piece of paper has to be fitted to the next like a jigsaw. But as a fun project with no expectations it's a great way to kick start your creative juices. And that's what art should definitely be about- having fun.