I am a first time iguana owner also...I think I may have been fortunate when it comes down to temperment. Our Newbie was calm from the moment we got him/her home...we have not yet (knock on wood) had any behavioural problem. As far as taming goes:
1) Keep a few treats (favorite fruit, etc.) on hand. (only use treats on occasion)
2) Resist the urge to let the ig go when it struggles. Keep a firm grip.
3) Hold him/her regularly. (I hold my iggy for at least an hour a day...he just chills out on my shoulder.)
4) When he/she starts to tame down a bit (and you are confident that you have control of your ig) I would let him/her chill with you while you watch television or something along those lines.
Here is a link that may help also (I didn't have to use these taming steps but they may help):
GreenIgSociety.org-Taming