What to do if i have just had a miscarriage and i want to try again as soon as possible. is this wise?

Not really: I would wait for at least 2 normal menstrual cycles before trying again. It is best to heal emotionally and also to get your body back to normal. When hormones have returned to normal, it is then possible to conceive with better success. A normal menstrual cycle is good proof of a normal hormonal cycle. Please do take your prenatal vitamins that contain folic acid.