I haven't done any sewing for years but having picked up a machine last year I'd tried to get back into it. So far I've only done repairs and hems, however I seem incapable of sewing straight and as I've got some curtains all cut ready to sew I'd better try and sort this out.
I don't remember having this trouble when I used to sew, any hints or tips so I don't ruin metres of curtain material?