#1
Techniques, websites, anything.

I think I have a pretty weak ear but I can tell major/minor apart pretty well. Anything beyond that is weak though.
PM me if you want to talk about the Red Hot Chili Peppers or hip-hop.
#3
Listen to a song and see if you can figure out the scales, chord progression or just any parts of the song and try and play it the same on the guitar. if u get stuck, look at the tabs and see how close you are...........it comes with time, your ear just kinda develops.
#4
Listen to simple songs and see if you can work out the chord progressions (with roman numerals). For example Scar Tissue by RHCP is I V vi V repeated. Learn what the chords sound like. Learn what chords lead well to one another (ii -> V -> I for example) and what that sounds like (for example V -> I sounds resolved and final, while V -> vi is only a partial resolution). Learning to hear chords this way is very important, imo.