I have irregular periods due to my PCOS, and its frsutrating not knowing when your next period is going to arrive, particularly when a cycle is very long...just makes the whole process of ttc feel more long winded cos you are waiting so much longer than everyone else to start a cycle. This is my first month ttc so I dont have a great deal of advice, all I did was check my cm several times a day and I noticed it went from almost nothing to very wet and then stretchy, I started testing using opks twice daily when it changed to wet, and when I got to a day when I had lots of ewcm I test and got a positive. I found I quickly got to know my body and could tell when ovulation was on its way.
Best of luck x