Pressing seams is a problem for me too. Rule of thumb, press toward the darker fabric but not always. Flying geese it is best to press away from the point but not always. I press my seams if my next piece crosses that seam. I use steam but lots of people dont. Always press down not like ironing a piece of clothing. You dont want to streach your pieces.
I like Eleanor Burns patterns cause she tells you which way to press your seams.
You can also press seams open if you have doubts about which way to go.