I make most of P and J's clothes from recycled materials. Some really good sources are woollen jerseys (especially merino), t shirts, pillow cases and sheets. They are cheap, you know what you're getting, and they contain quite alot of material. So I thought I would put together a little list of tips to get the most out of your upcycled garments.
I find it easier to place my patterns if I cut up the seams first. It makes it a little easier for the fabric to lie flat. Just make sure that you don't need the seams in your finished garment.
Put your pattern right to the bottom of your garment, its a ready made hem. Your finished item will be slightly longer, but you won't have to hem it (and really, who likes hemming anyway?)
If your garment has some special motif or pattern that you want to include, place your pattern pieces carefully, to make sure you can get it into the finished item.
Sometimes preloved garments don't always sit as perfectly as new material would. You can try pulling it gently into a squarer shape (carpet or microfleece is quite good for 'sticking' to other material). Or you can just line up your pattern pieces as best you can. The jersey above has quite a large rib section at the bottom, which naturally pulls in. I don't mind if the finished top also pulls in at the bottom.
I don't pin my pattern pieces to my material, I just use weights. And you don't need fancy sewing weights either, small cans of food, puzzle pieces or your children's wooden toys work just as well.
When making a top from a larger top, its a good idea to take the body from the body, and the sleeves from the sleeves. It means that you can be sure the grain of the fabric will be going the right way.
If you can get the sleeve pattern piece to fit at the end of the garment sleeve, you can eliminate hemming these as well - but it generally only works with short sleeve garments. Think really carefully about where you cut sleeves, as there is quite alot of fabric in a sleeve (I usually cut the underarm seam and lie it flat) that can be used for other things. I managed to get a sleeve for the top I'm making, and a baby hat from the two sleeves of the jersey.
A size 2 top for J, and a baby hat from one smallish woman's jersey.
With a little bit left over to felt or use for little woollen dolls.
I hope these tips are helpful. Let me know if you have any other questions, or have some tips of your own to share.