I generally try to not worry about it. I knit for fun, so if I don't feel like knitting then I don't! (This means being careful about promising things to people.)

The best thing I did for my knitting pace was learning to knit without looking, so now I can knit while I watch tv. It's sped me up quite a bit, unless the project is complicated. And it helps to remind myself that even knitting just a row or two will get me there faster, when a project seems like it's not going anywhere. If you can pull the project out and give yourself permission to only knit one row and put it away, then your project will get one faster than if you don't touch it at all!

But mostly, if I don't feel like knitting, I don't! it's not my job. :-)