Ttc again

After my 1st miscarriage I it took me 4 years to get pregnant again the only thing I did different that month was take evening primrose oil pills for my acne. Sadly that pregnancy also ended in a miscarriage. I want to start trying right away because last time it took us so long. I've been wondering if the pills helped me get pregnant or it was just a coincidence. Did you do or take anything to help you conceive? Or any advice on what can I do to stay pregnant, thank you ♥️.