You also may want to consider your mental approach when trying to get high. The first time I smoked, I was pretty nervous about everything, and on retrospect, I probably did get a little high, but I didn't notice at the time because I was so worried. The effects are subtle, and you kind of have to let yourself go. The first time I got high, it probably took around 20 minutes for me to notice it. After becoming more familiar with the effects, I can feel it almost instantly after a big bong rip.

Relax, relax, relax.