Suggestions on what to do differently?

Hi ladies! After suggestions on what to try new this cycle! Currently cd1 again! Cycle 4 after a miscarriage, cycle 7 all together! We have 1 daughter so we know there were no issues! However now my luteal phase is 9-11days so guessing that is now the issue! We are going to try smep again this month I think. I take prenatals, hubby takes the male version. We're both ideal weight, mid 20s, non smokers & not big drinkers. Both caffeine free & eat a fairly good diet! I get plenty of ewcm so don't think I need preseed or anything do I? I think I'm going to start the b complex vitamin I've got although it makes me nervous that I could make things worse some how! Just want to feel like we're being proactive! Any suggestions would be greatly appreciated!! Xx