Track ovulation
Don't have sex everyday- have it every other day (the sperm need a tad longer to regenerate properly, especially if the bloke is a bit older - google it, I'm not making this up). Also you really only need to focus on the sex around ovulation time.
Use pre-seed - Google it, you can get it from larger Boots that have a good section for TTC. It's absolutely amazing stuff - read the reviews.
Take your vitamins
Track your cycle
Don't forget your own orgasm after his. There's a biological function to the female orgasm - it launches the sperm inside you and really helps push it up. So once it's in - make sure you then finish.
If you like a drink, have a drink (not excessively but you don't need to ban that Friday night glass of wine if you usually have it).
Eat well for sure but don't ban foods, don't start throwing your body into any sort of shock diet. I can't stress this enough - don't start frantically exercising if you're not someone who exercises. That sort of thing.
Stress is nature's natural contraception. So the best thing you can do is make just those minor adjustments - the vitamins, a few more veggies on your plate, one less cup of coffee - but don't go mad. Eat well but don't start doing any detoxing.
Get outside, take some walks, be a bit more in nature, do things that make you happy.
Your DH needs to keep his balls cool - back off from jacuzzi's, tight boxers, hot baths, sitting with his laptop on his lap etc.
We did all the above, conceived the 2nd month of trying. I was nearly 40yrs.