Safest feeding regimen is Feed, water, water, water, Feed and take notes so that you can adjust as needed for future grows. So if you see a deficiency at week 3 you'll know to supplement next time at week 2. Here's some other tips for troubleshooting:
Is only one leaf affected? Yes = Invaders (bugs, mold, mildew), No = continue
Are leaves clawed, puffy or bumpy? Yes = Over Watering, No = continue
Are the leaves droopy, thin and curled under? Yes = Heat stress from light, No = continue
Is the plant growth stunted and leaves/tips yellowing? Yes = Nute Burn, No = continue
Is there any purpling cupping or folding leaves? Yes = Mg deficiency (purpling is also an early indication of over watering)
Are leaves drooping but still flat with no discoloration and media is dry? Yes = not enough water, No = continue
Are leaves drooping and media wet? Yes = sudden wilt, so sorry for your loss
Note that a few random leaves dying is perfectly normal and at about week 6 - 8 in flower you should see more leaves start dying off which is normal. Prior to weeks 6 - 8 any more than a few random leaves is a problem.
Micro def - show at top of plant first (rare, if you have micro deficiency you probably over watered and damaged roots except in the case of Mg which is the most common micro def)
Macro def - shows at bottom first (N is most common Macro def especially in early flower - refrain from dropping the N until after the stretch)
Too Many Nutes - shows at the leaf tips first
Too Few Nutes - pales from the bottom upward (typically N deficiency but also can be attributed to not enough light, for example when using CFL or incandescent)
