When weaving crosses string one ahead it make it easier. Wen straightening straighten one behind it makes it easier. if you straiten a string between two tensioned crosses the string you straighten will remain where you put it. The best way I have found to keep sing straight is to keep them straight as you go.
For weaving crosses I prefer to start going over the outside mains. i have RA and it makes it easier. The only time I don't is when I will end up with an anchor string going under the intersecting string that is very close. I don't think it really makes much difference either way.
I have the ability to drive people crazy, not sure if I was born with it or I learned it but I'm damn good at it.