The goal is for the cat to learn to associate the carrier with positive experiences and routinely enter it voluntarily.
The best carriers are inexpensive hard-sided carriers that open from the top and the front, and can also be taken apart in the middle. An easily removable top allows a cat which is fearful, anxious or in pain to stay in the bottom half of the carrier for exams. We can often do the whole exam in the bottom of a well-designed carrier.
Avoid carriers that require a cat to be pulled from or dumped out for an exam.
Choose carriers that are sturdy, secure and stable for the cat.
In the beginning, you may want to use just the bottom half of the carrier, or remove the door to allow easy access for your cat.
Make the carrier a familiar part of furniture at home, placed where your cat already naturally enjoys sitting, with soft bedding for comfort.
If the cat responds favorably to treats, catnip and/or toys, place these in the open carrier. You may even decide to feed your cat in the carrier in order to form positive associations.
It may take days or weeks before your cat starts to trust the carrier. Remain calm, patient and reward desired behaviors.