tips on using OPK

I'm starting to use LH strips for the first time this month, anyone have any "need to knows" or tips? 
I'm on CD 8 (havent started using them yet) I had a 29 day cycle which is the first "normal" length cycle I've had since my MC on 11/28/16, I just finished my third period last week. My other cycles were 36 days, then 33 days then 29 so I finally think my body is back to normal. Hoping to conceive this month! Thanks in advance 💛