Newbie to the whole ttc thing...

Okay, so ive been going through the posts and comments and just have a few questions, well no, let me put it this way, my husband and i have just started ttc...ive been seeing things like mucinex or robitussin to "thin the cm" is that right? I am overweight and we both smoke and drink (i know that we have to stop asap) but what other tips or tricks have you guys used? And what exactly does taking prenatal vitamins or folic acid while ttc do?