OPK Newbie!

Crystal • 1st IUI: 11/14/15, BFP 11/27/15! Miscarried 12/4/15. 2nd IUI: 12/20/15, BFP #2 1/2/16!!!
I just had a wonderful conversation with my DH about our plans for "this month." Only 4 months down so far of actively TTC, but been married 5 years and together 10. Finally at the right time in our lives! Beginning OPKs this round... Any advice from anyone on those? I'm planning on using Clear Blue Digital.