Extruder clicking / skipping help?

if the clicking/slipping is grinding off plastic instead of advancing it,  then you probably have a clogged nozzle or your extruder temp isn't high enough.   there are many how-tos and techniques to unclogging nozzle on here and elsewhere.  not knowing exactly what we  are working with i can't give specific advice.   

i will mention a couple of things i did wrong when unclogging:

You might be able to unclog it with a piece of e-string guitar wire.  Be careful to not scratch the insides with the wire.

If you get to the point of having to remove the nozzle from heat break dont force it.  I ruined mine that way.   I think you have to unscrew it while it is hot and the plastic is molten.   Mine was a stock solidoodle hot end so it wasn't a huge loss.

edit:  watched first video.  That is exactly what i saw so i stand behind clogged nozzle or too cold extrusion .. maybe add 5 deg to your hotend temp assuming you are not already at some really high level. 

also,  the filament clamp might be too tight.  i also ran into this problem before i diagnosed the clogged nozzle.  Typically it only needs to be tight enough to engage the teeth into the filament.  a symptom it is too loose is where the wheel is smoothly grinding the edge off the filament (ie no jerking.. )