I'm currently taking a preconception vitamin. But I also take the following:
Vitamin D
Co-q10 (improves egg quality)
Evening Primrose Oil (from the end of AF until O. It increases CM)
I started taking Maca but it gave me a sore tummy so I stopped.
Other things you can take that can help are Vitex but use with caution because it can make cycles irregular. Only take Vitex if you have long, irregular cycles. Baby aspirin can help support lining, but if you take it and then get a BFP it's important to keep taking it and let your doctor/ob/midwife know and they'll tell you when it's safe to stop. Inositol can also be helpful, but I've never really read up why because I take Metformin and that's meant to be similar.
If you are having problems with your LP, like spotting before AF or a short LP, you could try a B vitamin or natural progesterone cream.
A few months ago I also made sure DH was taking a preconception vitamin too. It takes 3 months for anything to help the swimmers, so it's worth starting ASAP. Zinc and selenium is important for men.
Lastly, if you've been trying for a while and having no luck, see a doctor. Lie a little if you have to about the length of time you've been trying. I knew in my gut there was something wrong but we wouldn't have gotten any serious answers if we didn't say we'd been trying for at least 12 months. Turns out I'm not ovulating regularly and start Clomid next cycle.
Good luck.