When I came off the pill last December I hoped it would happen within a couple of months for me.... I had been on the same pill for 10 years and hoped my body would just go back to normal.
My first few cycles were 29,31 and 30 days.... I kept thinking I would probably ovulate around the 14th so from around then that's when we would dtd the most...
Then my cycles got a bit longer... I started having 34-35 day cycles and even had one that was over 55 days. This was totally unpredictable and obviously made it hard to pin point ovulation and the months just dragged.
I tried charting my bbt but that method didn't work for me because I was doing shift work including nights so it was hard to take my temp at the same time in the morning every day.
I started using clearblue digi OPKs coincidentally around the same time that my cycle started to regulate.
I started having 34-35 day cycles more consistently and for 3 months in a row I got a positive OPK on cd20.
Knowing that I was ovulating a bit later we started dtd (for conception purposes) around cd16 and would basically do SMEP (google it) - which is basically where you dtd every other day and when you get a positive OPK you step up a gear and dtd every day for 3 days... Skip a day... Dtd one more time.
Anyway I actually conceived the 3rd month of using digi OPKs and only wish I started using them earlier cos we spent months dtd at the wrong time of my cycle!
I had my 12 week scan on Wednesday and everything is perfect 
So I conceived in September ... 9 months of trying but 6 of third months we were, a lot of the time, focusing our efforts at the wrong time of the month!
Lots of people say to just have lots of sex.. At least 3 times a week throughout your cycle. That's fair enough but that was not possible for me. I was working crazy shifts... DH often works away... We have low-mediums sex drives anyway and both commute in and out of Central London most days... Getting up at 5am and not getting home til 8-9pm some days... Let alone when I was doing night shifts! So it just wasn't possible for us to have sex every other day through out the month! Nor did we want to 
This is a really long post... Sorry!
If you can have lots of sex throughout the month then just do that! If that doesn't work for you, I would strongly recommend clearblue digi OPKs and SMEP.
Make sure you record everything - I used a couple of different iPhone apps.
And one last thing... Pay attention to your cervical mucous.
In the last few months of ttc when I was using OPKs, I also finally started to notice EWCM which would start to appear in the few days leading up to a positive OPK.
When you start to see EWCM, start dtd more because it means ovulation is on the way 