I like to do things in small increments or "chunks" so that a big project isn't too daunting, whether it be household chores or any crafty/sewing project. It gives me a goal to achieve as well as feeling good about doing it. AND it gives me permission to put a project down once I accomplish that goal.
For instance, in cleaning up the kitchen: I try to take 5 minutes every day to do one thing in the kitchen -- put away the dishes or put dishes into the dishwasher or to wipe down the counter/stove.
After all, five minutes isn't a lot of time, and can easily be accomodated into my day. Then I feel accomplished and not so frazzled thinking about cleaning up a whole room.
When sewing, I break out a project into manageable chunks. For example:
1) get a pattern drafted (or cut out the pattern pieces)
2) getting just the fabric cut,
3) sewing just 1-2 logical pieces together
etc.. Then I work on just that single chunk so that a big project can be made more manageable.
When knitting, I'll try to do things in increments, like 1-2 lace rows or 1-2 inches of a given sock.
When spinning, I've been following Jasmin's example, and only spinning one ounce at a time. While this might have a few disadvantages (like never having enough quills for large amounts of fiber), it does break amounts down to sizeable and MANAGEABLE one ounce chunks that I can easily deal with, instead of frustrating myself thinking about the number of "pounds".
After all, you should eat pie in slices. Trying to fit the whole thing in your mouth is not only messy, but very impractical.