This is in response to Courtney's question about how to make a pattern fit you that may not be written to fit you the way you want.
1st: Measure yourself, and determine how you want your sweater to fit. A fitted sweater will need a little negative ease due to the fact that knit items tend to be a bit stretchy. Say you have a 30" waist, you may want your finished item to measure 29"at the waist to fit more closely. Keep this idea in mind when determining how many stitches you will want to do for your sweater.
2nd: Knit up a gauge swatch. This is your key to figuring out how many stitches you'll want for each part of your sweater. A gauge swatch is simply a 4"X4" knit piece that helps you to see how many stitches and rows you get with your yarn and needles. Since every knitter is different this is very important in assuring that your sweater will fit you when you're done!
3rd: With your measurements and gauge swatch in your hot little hand you're ready to cast on! I would suggest casting on the number of stitches recommended for the size you want to make if your gauge swatch is anything close to the gauge suggested for your pattern. I often have to cast on 3 or 4 times before I'm satisfied with the size, but the pattern gives you a place to start. What I do is cast on, knit a few rows, and try it on by slipping most of the stitches onto waste yarn, and slipping it on. If it looks like it'll fit just keep going, if it's too big or too small start over using your gauge swatch and measurements to figure out how many stitches to start with the next time.
Once you've cast on the right number of stitches , and knit the first bit of your sweater (in this case the neck of a sweater) follow the pattern for increases adjusting how many increases and the frequency of them to end up with the right number of stitches for you. I also suggest trying on your sweater when you're 1 or 2 increase rounds away from what you think you'll need because sometimes knitting stretches more than you think, and you'll actually need fewer increases than you thought you would, and sometimes you knit tighter than you thought, and you may need more increases than planned. Use the same idea for decreasing when you get to the waist shaping.
To make a sweater shorter or longer than the pattern you'll also want to use your measurements and gauge swatch. If you're taller than average you may need to add some rows, if you're short you may want to take some out. I try to take rows out where they will be less noticeable. This tends to be where there is little to no shaping. So when your pattern says to knit straight for 3" but you're 2"taller than average you'll want to take a measurement of your length in that area, and add length accordingly. In this sweater pattern you would knit straight from the last increase row until just a few inches above your natural waist when you'll start decreasing. So just knit straight a couple extra inches if you're tall (a couple less if you're short like me!). Adding and subtracting length is actually really easy! That's also one of the beautiful things about knitting for yourself! You can always make things the right length! :)
I hope this is helpful to people. It's just kinda what I figured out through my trial and error methods.
And don't forget that gauge swatch!!