I'm guessing that maybe you are something like an anesthesiology or ER resident on the medicine service? Just guessing...
Presenting is a pain in the ass sometimes and is something that a lot of medicine attendings and fellows fixate on. Never mind that it doesn't tell you everything about a person's doctoring ability or understanding of a patient. Many will judge you primarily on this, which I think is kind of silly since it's only 1 reflection of your abilities. Some people are better at this than others. I would say if you need to go back and look at one of those med student books like "First Aid for the wards", which has chapters about how to present patients in different specialties. Also, I would say the 1st sentence or so is very important (where you either give a summary of what happened overnight or you are presenting the chief complaint of a new patient). After that people stop listening as much...
Also be sure and have the latest lab and imaging/test results at your fingertips if it's the medicine service, but you don't have to necessarily mention them all if they are normal or unchanged.
People in medical school used to say they practice in front of a mirror, which I always thought sounded kind of silly but in hindsight I think I should have done that, since presenting patients is a skill learned by repetition.
If your upper level resident is friendly (if there is one), you could ask him/her for suggestions as well.
The fellow sounds like kind of jerk, by the way. Saying "You don't synthesize information well" really isn't very good feedback. It's just a general criticism. If he/she had wanted to be helpful, more specific feedback should have been given ("When you presented the overnight events on Mr X this morning during rounds, I noticed that you didn't mention the results of his cardiac enzymes, which were negative overnight, or the fact that he had a stress test that was still pending...").
