Thanks for the awesome info! These are the top problems I’ve had: Heat creep, hot end temperature too low, nozzle too close to the bed, inconsistent filament diameter and dust/particles that get stuck.
When particles get stuck, I also use the cold pull method:
Step 1: Heat the nozzle to printing temperature and manually feed about 10cm of filament through the hot end (where the bowden tube was). Try and keep the filament as straight as possible. Natural or clear coloured filament works best so you can see the residue when you pull it out. If your hot end is too clogged to get anything out of the hot end, take a thin wire and a pair of plyers and stick it into the tip of the nozzle to clear the blockage.
Step 2: Once you have some filament coming out of the nozzle, bring the nozzle temperature down (120C for ABS, 90C for PLA, and 100-140 for Nylon). Try to use the lowest temperature possible for this step. It should be hot enough that the filament is malleable but not so hot that it is too soft. Be sure to cut any filament off that is dripping from the nozzle before you start the pull.
Step 3: Pull on the top of the filament until you feel it start to slowly give out. If it comes out too easily and there is no residue on the end, lower the temperature. If you have trouble pulling it out, raise the temperature until it does.
I give a more detailed break down of fixes to some of the other problems as well in my blog. Hope this is helpful!