As was said, experience will be the biggest speed booster. Once the muscle memory takes over, you will start shaving seconds off of the time needed to make any item...you'll be reaching for things before even thinking about them.
Some general advice:
1) organization is key. Some of this will come in time, but other things you might need to think about. Usually you can have some leeway in how you set up the station, so use that to your advantage. Keep ingredients for the same item near each other. Before service, make sure you have everything properly stocked, including appropriate back ups. Make sure you have all utensils/smallwares needed to work your station, including any backups here as well. (i.e. have sufficient tongs, ladels, towels, etc..ready to go).
2) Economy of action. This is king in the kitchen. I can work circles around younger, faster cooks because I think through my actions quickly before taking them, and plan ahead beforehand. Anticipate! Look for ways to reduce movement...minimize the likelihood of having to leave your station to go to the walk in or dishtank or trash. No handy trashcan nearby? Use a sixpan or a small cambro or some other small container to dump scraps and other small things in, then you can dump that in the trash when you have a second or two free. Or if you have to reach into a low boy, grab everything you will need in one go (think ahead for the next few tickets), to minimize the amount of time needed to bend over and dig around. Having to run to the dishtank often? Set up a hotel pan on a bottom shelf to temporarily store dirty dishes, then you can dump them all at one time instead of making multiple trips. Every step you can remove, every action you can eliminate, every second you can shave off, speeds you up considerably. Lets say through maximizing your economy of action you can shave off an average of 5 seconds from the time needed to make every item. At 700 covers a night, thats 3500 seconds...thats 58 minutes worth of activity eliminated. That might sound extreme, but its true, thats the level of savings that can be achieved. And think how much less work that is!
3) Work clean! You can't stay organized, you can't work fast, if your station is a mess.
4) prepare multiple similar items at the same time. Say you have three tickets coming down, and they have a total of 8 dinner salads on them. Instead of making just the salads for the first ticket, make them all at once. You can put 8 salads together in assembly line fashion faster than putting together 2, then 4, then 2. Obviously this depends on space and timing and other issues, but the idea is to assemble similar things at the same time when possible.
Garde-manger is usually the most intense station as far as energy and activity needed to get tickets out. First, alot of your items are order/fire, so as soon as the ticket comes in you are needing to plate. Other stations might have a course or two or three to get ready before fire, and the hot stations will have items that need time to cook, so they can manage timings easier for each ticket...i.e. while this is cooking I can be doing that. Second, you will get hit harder before anyone else, so as they are getting a chance to ease into the service you are already getting blasted. Third, every item on every plate requires activity to put together, and you will often have more items on a plate than the other stations. A meat and 2 side plate might have 4 or 5 things that need put on that plate, and a lot of it might already be prepped and ready to go. A salad plate might have 10 or 12 or more things going on, and some of it might require additional attention (slicing this, stacking that, arranging this, etc..). But this is why this is often the first station a new cook gets to work, so that you can see how well the cook manages himself and his time, how clean he works, and how quick he can move. And that newer guys tend to have a lot more energy! (that, and the ingeredients are usually a lot cheaper, so a mistake isn't as costly as say overcooking a ribeye or screwing up a fish)
If your fellow cooks aren't getting mad at you for being slow, then they don't think you are too slow, at least given your level of experience. If they did think you are slowing things down, they'll let you know. So you are at least above the baseline. And if you focus on all the little things you can do to speed yourself up, and get faster as you get more experienced, you'll be where you need to be in no time.