First, get the suit tailored to fit you. Even a cheaper suit that has been tailored to the wearer is going to look a lot better than an expensive suit that has not. A good pair of well kept shoes and a strong tie are a must. Anything else is personal preference/style/situational. I tend to go classic. An understated belt to match the shoes. I do wear higher end ties, but I don't wear items that scream their brand all over it. I am not selling for them, I am selling myself. Going classic also helps to eliminate things looking dated so quickly.