We have tried several different harnesses for our dog. This is the best we have found. It's easy to adjust and put on. There are two attachment points for the lead, so you can choose a position that suits your dog. It's a close fit, so your dog can squeeze under gates, or dive through hedges without getting stuck. There is a small ID pocket, where you can put the dog's tag, with his/her name and your phone number. The adjustability makes it unlikely it will chafe your dog.
Ruffwear makes a variety of "Dog wear". I want to get him a set of panniers, so he can carry his own food on camping trips!