avoid raw food, soft eggs (unless pasteurized including milk and other dairy products), unwashed veg and fruits, junk foods, none or little amount of caffeine … go for healthy foods veg fruits proteins beans (all cooked well) these are everything for baby development as you’re at the most vulnerable stage of pregnancy. take folic acid till end of firat trimester
If heartburn like I did too during first tri, I avoid food that triggers esp spicy, greasy foods and potato, tomato etc. Ask ur gynae if it's OK for u to have Gaviscon advanced cos I had it but I took half dosage to keep food down and not to feel too much burning in the chest. Hot milk before bed and sleep upright till the heartburn goes off.
Take folic acid which is important for baby development for trim 1 . Avoid raw food , alcohol and smoking :)
Eat more … baby need nutrition