I've been getting a few questions about appropriate yarns, so I thought I'd go into it a little further. I think in my first posts I just said, "Get some yarn!"
We're looking for worsted (10-ply) or DK (8-ply) yarns. When I'm getting ready to start a project, there are several places I look for hints about what yarn to use. My first stop is generally the pattern page on Ravelry. These are public, so you don't have to be a member to view them.
Just above the pattern name is a series of tabs. The pattern page opens to "Details" - this gives you all the information you need to shop for the pattern: yarn, needles, gauge, yardage.
The second tab is "Yarn Ideas." If you click it, you'll see a list of all the yarns that other Ravelers have used for this project:
Beneath any given yarn, it says how many times it has been used. Clicking that number will take you to all the projects for this pattern that have been made in this yarn. Nice, huh?
Going back to the pattern page, on the right side is a box called "About This Pattern" - at the bottom of the box it tells you how many projects have been done with this pattern. When I'm starting a new pattern, I almost always spend some time looking at the finished ones already on Ravelry. It gives me good ideas about yarns to use, changes to make and sizing.
If you have an idea about a yarn you'd like to use but want more information about it, you can enter its name in the "Yarn" section of Ravelry, following the tab in the top row of any page, to the right of the Ravelry logo. I often find it helpful to read the comments on a certain yarn if I haven't used it before. Another good place for information about specific yarns is Yarndex.com. It's always important to find out the gauge and yardage when substituting!
I often like to shop for yarn from other Ravelers' stashes. When you find a yarn you want, go to the page for that yarn. Under the yarn name are tabs; choose "stashes". Once you're on the "Stashes" page, use the drop-down menu to set the status (all the way to the left) to "will trade or sell." You can often get yarn from other Ravelers for a much lower price than anywhere else, if you're willing to be flexible about the color.
Many etailers have options that let you view yarns by weight: KnitPicks and Webs are among these. Even if you don't end up ordering from them, you can still often find good information on their websites!
I hope these resources are helpful. Of course, I'm always happy to answer questions if I can!