conceiving help

My husband and I have been trying to have baby # 2 for about 4 months. I know it's not that long but I'm wondering why it's not working lol I have been tracking my period and using the iperiod tracker app.... and having inter course on all the green fertile days and the ovulation flower day. And nothing. Was so easy for #1... can any help! Any tips please :) Should I be trusting an iPhone app!!!?? Lol