[Kosmo]

For a complete suit, I've gone to a men's clothing store. They can do minor adjustments. For separate suitcoat and trousers, I've taken the jacket to a tailor for adjustment which would incur additional cost.

Difficult to have major adjustments for a perfect fit unless bespoke (think The Kingsmen movie).

Hope that helps.

Edit to add which style you like: Dbl or single breasted, length, type of lapel, vented or not, etc. Lots to consider depending on your body type.