(note: I am new to cycling so please forgive my ignorance and help me learn)
I bought a Giant road bike back in December(I can't remember the exact model because I had to ride my cruiser to campus today due to the problem I am about to state) with 650 wheels. I recently had to buy new tubes (about two weeks ago) because the tubes that came with the bike ended up puncturing while I was trying to pump the tires. So I've started to utilize a new technique of putting the spickets at the 12 o'clock position before putting on the pump, pumping to the desired psi, then taking the wheel b/t my legs and using both hands to pull the pump straight off the spicket. Beforehand, I was jiggling the pump on and off the pump, which I suspected was the original culprit. However, this morning, I just punctured the tube again ... and ended up being late to class but that doesn't matter. I am just enraged that I just spent $32 just two weeks ago for new tubes and that I am going to have to spend another $16. What am I doing wrong? Any tips?

Leilani

P.S. Since it seems that I would be changing my tubes quite often, would anyone mind showing me how to change them? I've seen people change them several times but I am quite wary of doing it myself.