Ttc question

Does taking prenatals while trying to conceive boost your chances? I've been ttc for 7 months and my husband is trying to help me stop smoking. I usually smoke about 6 cigarettes a day and today I've only had two and haven't really been craving them as much. Probably because I want another baby more! Anyway. I'm just wondering what kinds of things can boost my chances. I have one child already and we got pregnant with him the first time that we tried so I know I can have kids. It's just been very difficult ever since I got the depo shot. I only had one shot and I didn't like the symptoms it gave and now it seems impossible to get pregnant. So anything that can boost my chances I will do!!