I've got a few tips. In college I worked at a plating company. We did zinc, cad, nickel, chrome, silver, copper, etc. It helped tremendously to be able to tell a good chrome job from a bad one. Now when I get my parts chromed, I can spot the less than optimal results. Luckily, my local plater is honorable, and will quite willingly re-do a part if I point out work legitimately needing re-work. So there are a couple of points: Learn what is good and what is not so good chrome. Find a plater who is local and reputable. Don't take all your parts at once. Take a few to start, and see how the work goes, and how the relatioship develops. Inspect the parts at the shop before paying, preferable in the sunshine, where flaws will show better. Have photos of each part before leaving them. Disassemble all parts completely. I do mean completely. Get price quotes in writing. Have the plater give you a time frame. Don't just drop them off and hope. Be patient.
Chrome plating is an inexact art when dealing with, to the plater, unique parts. Understand that a reputable plater does not want inferior work leaving his shop any more than you want to have inferior plating on your car. Finally, be prepared for high costs. Plating is highly labor intensive, and proper storage, use and disposal of plating materials is very expensive to the plater. There are some parts which make more money sense to buy new, already plated. Some parts are definitely worth re-plating, though.
Good luck. There's not much more satisfying than putting on a well plated part during final assembly.