Bananas are high in folic acid, I believe greens are too and spreads like marmite. Some cereals are fortified with folic acid and there will be some in your pregnancy multivitamin tablets
Spinach is high in folic acid. Cereal is a great way too. I've been deficient in folic acid before and I take my prenatal vitamin and every week and folic acid vitamin to make sure it is not to low.