I've got my second batch of homebrew fermenting, and in just two batches I've learned a lot the hard way (messed up batch priming, possibly under-aerated the wort, etc)
What steps are critical to any batch of homebrew regardless of recipe, equipment, or approach (extract, all-grain, etc)?
I found a good partial answer in another question: Shaking vs not shaking
EDIT: As far as a best practice, I would SAPS it :D (FYI, I made that acronym up...)
Starter - Create a starter to get the cell count high enough - http://www.howtobrew.com/section1/chapter6-5.html
Aerate - Before pitching, use one of the many available methods to aerate the wort - http://www.howtobrew.com/section1/chapter6-9-2.html
Pitch - When the starter is ready and the wort is aerated, put the yeast into the wort in the primary vessel - http://www.howtobrew.com/section1/chapter6-6.html
Suffocate - Do anything possible not to introduce oxygen after this point - http://www.howtobrew.com/section1/chapter6-9-3.html
It is not recommended to perturb the beer between when fermentation starts and kegging/bottling because you run a strong risk of coming into too much contact with oxygen. Carefully racking to secondary with minimal oxygen exposure will leave you with plenty of yeast for carbonation.
Please see Why do you aerate wort at first and try to keep oxygen out later? for why oxygen is not good for wort/beer once fermentation has begun.