All good stuff - may I throw these in?
In addition to scanning up and down, keep switching the range from close in (20 - 80nms) which is your tactical picture, to far off (80 - 320nms) which is your strategic picture. It's all too easy to get deeply involved with the close in one, only to discover when you have passed it that you are heading for a 'dead end' or a 'sucker's gap' which could have been avoided with strategic looks earlier on.
Try to go upwind of the big ones and be aware that, broadly speaking, CBs travel roughly with the 10,000' wind which may be significantly different to the wind at your cruise level if you are taking their drift into account on a long 'look'.
Cheers,
mcdhu