No chalk lines. Learn how to shingle right before you go for speed. Learn how to shingle in many positions and both directions, right and left. Shingle in a stair step pattern and cut the shingles as you go, beginning and end. Lay the bundles out 4 feet up and 4 feet apart all over the roof before you start. Get a rythm (sp) on your nailing. Don't try to go fast, get them where they are supposed to be. This is my system and I haven't found anyone who is even close to as fast as us.
Another thing, ask yourself if you are working as hard and eficeintly as you can. If you can honestly answer yourself, you will get better.
I can easily hit 4 square an hour on a walkable pitch if I feel like it.
Not as fast as you (not a full-time roofer), - - but everything you say is how I was taught, - - very few or no lines should be necessary, - - stair-step is actually much faster once you learn to lay it out fast. I cut the starters before even getting on the roof, - - the cut-offs go to the other end.
Also, - - as far as hand-nailing, - - never heard of a 'nail-tin', - - should be able to 'fumble' the nails into position (in your other hand) as your nailing off. - - never miss a beat. I prefer to always use 1 1/2's, - - 1 1/4's seem much harder to fumble.