$1911

When I make a bracelet I find it doesn't look like the picture. (Maybe I am being hard on myself.) I feel like I am doing something wrong. I know the four basic knots and how to read patterns. I started with easier patterns and worked my way up to harder ones. With a larger number of strings (8) I find it hard to keep the strings straight and keeping them from getting wound together. Then I try to straighten them and get frustrated.

I use a clipboard to hold the strings together or my bracelet loom.

Or the bracelet will get twisted as I make it. I couldn't find an edit button for my post.

Can you show us a picture? It's hard to give advice without seeing the bracelet. It sounds like you're not putting the strings at the right side of the knot, what could explain the twisting.

Sometimes if you are pulling the strings too tight it will curl quite a lot at the edges, which can cause string confusion.

Kleinevos: yeah I can get a pic up.

If your strings are getting tangled and mixed up, they have looms that have slots to hold strings for you. Just google "My Friendship Bracelet Maker" or "iLoom" and you should find some :)

That iLoom is very fancy, but so expensive (plus it requires owning an iPad, too)!
In addition to the original MFBM, there's a "clipboard" version that is thinner, lighter, and easier to use on your lap. It's also cheaper. I bought one on eBay for $10 (although I think the original is $10 off on Amazon, making it only $15).
There are ways to make a makeshift loom for friendship bracelets, using a standard clipboard with a strong metal clasp, and a piece of cardboard that has been cut into a half-circle and has had slits cut into it to hold the strings. As I said, I decided to buy the MFBM clipboard, so I haven't tried the cardboard yet.
There are also some macrame-specific tools that make it easier. I found a long, thin metal "needle" (there is no hole) that is used for pearl knotting, to get closer to the pearl, that helps with knotting and also helps with unknotting if you make a mistake. (I found that one on the Knotty-Do-It-All page, but I'm sure they're sold elsewhere, as well.)
I also found a foam board for macrame (this one I bought from Marion Jewels in Fiber) that is a good shape for this, very light and easy to hold and has the slits cut into the bottom semicircle. I found the slits are a bit too far apart to make it absolutely ideal for friendship bracelets, but it's an inexpensive option that does help.
The problem I keep running into is keeping the sides aligned straight. I have no problem with keeping the bracelet flat and not curling, my problem is that specifically when making a candy-stripe bracelet, each new color wants to realign itself and go in a different direction. I'm keeping the knots very consistent and using the MFBM clipboard version, so have good tension as well, and I cannot figure out how to prevent this. Someone somewhere suggested using regular clear tape to hold it down, and that helps make it look mostly straight, but I fear that as soon as I un-tape it, it will "zig-zag" again.