PreTTC DC2 - what more should I be doing?

[winterpansy]

I've one fantastic DS who is 16 months and we're planning to TTC DC2 just after Christmas. I'm taking folic acid (sanatogen Mum-to-be), exercising 3 times a week, eating lots of fruit and veg and I'm off booze. Is there anything else I should be doing to increase my chances of conceiving?
DS was a very happy surprise and I fell pregnant with him while on the pill (I'd been on it for 13 years). I haven't gone back on it as we knew we wanted to try for another baby in the near future after DS was born but not being on it has shown that my cycles are very irregular - anything from 28-49 days so I'm thinking I should get some of those ovulation tests to help know when the right time will be to DTD. I'm terrified of secondary infertility as have just watched my friends go through it and it was horrendous.

Any advice would be very welcome!