Well I've only done 1 and a bit so far and here's what I learnt.
Much easier to cut your squares and make up each block (front,wadding and backing) THEN saw those together.
Measure at least 3 times and make sure WELL pinned when you sew. I hand sew only and didn't double,triple measure and pin the backing well (did first peice the normal front the wadding and back) and well errm it's not a proper rectangle lol. The backing got gathered up in parts and too short in others hehe.
I just used Metal ruler and quilters pencil with scissors
Oh and ALWAYS lay out your design before comitting to sew
Templates do help unless your mind is very scatting and using odd size squares and you go meh and wing it anyway rofl. Oh dear maybe I'm not cut out for quilting but they do the job hehe.