At preconception advice clinic you and your husband will be screened for any specific medical problems or family history of any inherited disease etc, which could potentially affect your pregnancy or baby. If any such problem is identified from your history, then steps will be taken to improve and optimise your health ( in the case of any existing medical problems) or to quantify the risks ( in case of inheritable diseases in the family). All this is done before the pregnancy (ie preconception) so that chances of a good outcome are optimised, with reduction of risks. A definitive plan as to when to plan the pregnancy, and what tests are needed, along with which speciality doctors need to be involved in the pregnancy care, will be made. This will also provide you with the opportunity to meet these doctors and discuss any relevant issues, prior to actually falling pregnant.
I would advise you to start taking folic acid tablets daily, lead a healthy lifestyle with exercise and healthy diet, maintain a normal weight, if smoking or drinking to quit, and if there are any chronic medical problems such as high blood pressure etc, to see your doctor and get the medication and dosage reviewed, in view to optimising your health prior to pregnancy.