Knitting - When knitting sleeves, knit both at same time on one needle, that way they will always be the same size (even if you get the size wrong, at least they will be the same!).
Thread - If you are hand sewing use waxed thread which will stop the thread knotting. You can buy ready waxed thread or you can buy dressmaker's wax and wax the thread yourself which is cheaper!
Thread - Whenthreading your needle (machine or hand sewing) never wet the end of your thread as this makes it heavy. Best to cut your thread at an angle - which makes it more pointy - with a sharp set of scissors. Make sure you don't have any wee thread fibres left which is what causes all the problems when threading.
Fabric - This is a really disgusting one but it works! If you prick your finger on a pin and a spot of blood goes on your fabric, clean it off with of a bit of fabric with your own spit. It really does work, but it has got to be your blood with your spit, doesn't work with anyone elses! The old fashioned was to chew on a clump of thread and use that.)
Sewing machine -If you fabric is wider than your guidelines on your sewing machine, put a strip of masking tape on your machine to use as a guide line. Great when teaching children to sew on a machine.