If you want to successfully groom your pup for a show, it takes a little planning and hard work on the night before whichever show you're planning on attending. The biggest thing to keep in mind is that you need to groom your pup to meet their breed's standards. You can find this information online, or your vet, or another professional groomer may be able to help. It also means that you need to pay close attention to detail. If you trim Sir Bartholomew's coat, it must be perfectly even, nails must be trimmed back evenly and ground smooth, ears have to be clean, anal glands expressed, and more. Dog shows are notorious for being very strict with their guidelines and standards, so being able to groom and bathe your dog to fit those standards is the key to placing well in the show.
The biggest issue you are likely to have is getting Bart to put up with this level of grooming at first. In time, he will have learned to deal with it. But be patient, thorough, and gentle with him. Use positive reinforcement in terms of praise and treats to help get him used to the entire process. Show grooming can be a long, arduous process, so it's important to work up to that level.
The most important part of learning how to groom any dog for show is taking the time to learn everything you can about your dog's breed with regard to what show judges expect to see. Spending several months practicing the entire preparation process will help ensure you and Sir Bartholomew III are both ready for show time.