If your periods either re-establish or become much more regular, with a reasonable cycle length, that is a good indication that ovulation is occurring. Being aware of your body can be helpful.
Copious, clear cervical mucus is a good indication that ovulation is imminent. Ovulation pain, mid-cycle or mittleschmerz is another indicator.
You could always try using an ovulation test, which is based on detecting the mid-cycle LH surge that occurs just before ovulation.