Where you shoot from depends on whether or not you are allowed to shoot on the field. If you can shoot on the field you will probably want to shoot the batters from down the first base line if the are a RH batter, and third for LH batters. What I try to do is get shots of each player on the team you have been asked to shoot in their field positions as they are ready to catch the ball. Some of your best shots might be captured during warm ups or during while the players are taking infield practice. Their uniforms are clean then and you should be able to get some great shots. Then I usually try to get shots of each player batting on both teams. Between innings when the players are tossing the ball before the inning starts is another good time to get some photos of each player on the field. After you have shot all the players batting, and hitting. You can concentrate on taking shots of the game itself if a player is on first and has a chance to steal second etc. you have to try to anticipate the next play if runners are on the bases. If you can you want to shoot from down the first or third base lines as close as you can behind the first base, and third bases. Don't neglect the catcher, get them in position but the best shots of the catcher are going to be when the face mask has been removed for a throw or to make a catch. One of the hardest things to do is to get good shots of the players if they are wearing caps depending on the time of day the bill of the caps will cast a shadow over the players face that can be tricky to deal with. If you can shoot from behind the back stop, and I say if because so many have netting that covers the back stop from side to side behind the catcher, you can experiment with you 55 and 28-135 to get some shots of the pitcher throwing the ball. You want to try to get you lens against the fence links so the corners of the links are not in your shots or get a photo that you can easily crop to show the pitchers face as they throw the ball, and keep your lens there when you get a good framed shot, sometimes the best shots are the pitchers expressions after the ball has been delivered. If are not permitted to actually shoot from a position on the field you will have to try to take your shots from over the fence. If the shots are to be taken on their home field you might to do some pre game planning and see how tall the fence is etc. You might also want to introduce yourself to the coach and tell him you are there to take photos if the team is you have not already done so. You might also talk to the coach of the the other team and let them know you are shooting photos. One thing is the umpires control the game if you are allowed to shoot on the field get some shots of them also making calls etc. Once you have taken shots of each player in position on the field and at bat you can follow the action of the game an concentrate on taking shots of the players as they catch or bat. If you can shoot from inside the dug out during the game you can get some good shots there also. Don't neglect the shots of players inside of the dugout as they are watching the game also. Some good shots of the players in the on deck circle are good also. Here is a link from a guys blog that might give you some additional advice http://markhancock.blogspot.com …aseball-and-softball.html
A word of caution if you shoot on the field you have to keep one eye open and not get so caught up in in shot that you are victim of a thrown ball or worst a line drive. In some tournaments I have shot the tournaments are now requiring the first and third base coaches to wear helmets if they are allowed to coach from the coaches box down the first and third bases lines.
Good luck my first baseball is this weekend, it is still cold here in the mornings so I can only hope that the games I have to shoot are not 8AM games. It is a long season from February until..... Good luck hope this helps you.
One other thing you can do if you can not shoot on the field is remote one camera over the fence and focus on the batters box or the pitcher in action. That way you can have the best of both worlds so to speak and make the most of both cameras one set to take photos of the pitcher, or batter one that you can move around and take action shots.
One thing you may get asked, especially if a player hits a long ball, or home run is "Did you get that a shot of my son hitting that home run ?" I want to say which end of the play did you want the get the hit as the bat struck the ball, or a shot of the ball as it went over the fence ? I usually say sure did.