SANTA CLARA -- Michael Crabtree's advice to fellow 49ers wide receiver A.J. Jenkins is to focus on getting better every day.Accomplishing that goal is going to be more difficult than ever on Wednesday. After all, the rookie had his best day of practice Tuesday -- and perhaps the best day of practice any 49ers wideout has experienced during summer camp.But Jenkins said he didn't have to look too hard to find imperfections after a practice that saw him catch at least six passes during 7-on-7 and team drills, including a leaping grab 25 yards down the field between defensive backs Perrish Cox and Donte Whitner."Even though I had a good day, in the film room I saw things I need to work on," Jenkins said Thursday, a couple hours before the 49ers hit the field for an evening workout. "I need to improve on the simple things that you probably wouldn't see on the practice field but that we can microscope on film. That's what I'm focused on. Small things. I can't say too much, but small things."I'm not the person who gets into all the stuff about myself. I'm about the team. People have been saying I have bad practices all the time when I thought I had good practices."Cornerback Tarell Brown, when asked to list some of the fastest players on the team, mentioned Jenkins, the No. 30 overall pick in the draft. As Jenkins is getting more comfortable with the offensive system, he has started playing faster."It's becoming uncloudy for me now," Jenkins said. "At one point I was like, 'Wow, it's going to take me a while to learn this playbook.' Now things are starting to sink in and I'm playing faster and better, and playing with a lot more confidence."It appears unlikely Jenkins will be able to crack the 49ers' regular-season lineup and unseat such proven veterans as Crabtree, Randy Moss and Mario Manningham. So Jenkins' time to shine might be during the four-game exhibition season. His spot on the 53-man roster is not in doubt, but it might be difficult for him to find a role on regular-season game days.Jenkins is expected to see extensive time in the exhibition season, however, beginning Friday night against the Minnesota Vikings at Candlestick Park."My dad is going to be here," Jenkins said. "I'm excited to go out and showcase some skills, and when I have an opportunity, go make a play."The early reports on Jenkins were not flattering, as he admitted showed up to the 49ers' rookie minicamp two weeks after the draft unprepared for the amount of running required from somebody in his position.But Jenkins is in tip-top shape now. He has made it through the first 10 practices of training camp -- grueling three-hour sessions -- without any problems."I'm feeling a lot better than I thought I would," Jenkins said. "I'm not hurting. I'm fine. Legs are good. Feet are good. I'm not banged-up at all. I've been treating myself good. Randy Moss told me I need to treat my body like a new car."After some initial bumps in the road, Jenkins said he is gaining confidence with every practice."I'm getting more comfortable with the offense as the days go on," he said. "Right now, I'm just trying to stay consistent. I'm not worried about tomorrow."When you make plays and you see it on film, you get that confidence. And your teammates tell you, 'Keep working hard, you got it.' Right there, that tells you that you do belong here."