Here are a few things that have worked for me: Brush oil on the dough before applying toppings.
(Already suggested) Scoop out the seeds and guts and then dice your tomatoes instead of slicing.
This should get rid of some of the moisture.
Add cheese and then place tomatoes on top.
Stretch your dough evenly and not too thin.
I usually don't precook tomatoes (sauce at least) because it ends up getting gummy since they get cooked twice.
cooking.stackexchange.com/users/2098/raji
I always pre-cook my crust for 3-8 minutes, depending on whether it's thin crust or not.
Works great for what you're describing
but I prefer it even when not using fresh tomatoes,
I like a slightly crispier crust.
Never tried pre-cooking the tomatoes - you could squeeze them, maybe in a ricer, but you're going to lose some texture and a lot of flavor, I would guess.
cooking.stackexchange.com/users/1236/stephennmcdonald
Thin layer of olive oil on the crust before you add the sauce.
Just drizzle on a little bit and then make sure it's evenly applied with a hand.
cooking.stackexchange.com/users/2096/Robert Ellison
Whenever I use fresh tomatoes on pizza, I always put them on the pizza immediately after cooking the pizza.
That way they stay recognizable as fresh tomatoes instead of just turning to mush.
cooking.stackexchange.com/users/1307/David Norman
I pre-cook the crust for 90 seconds (>=450 degrees F) on a pre-heated pizza stone.
Problem solved!
cooking.stackexchange.com/users/1601/Goodbye Stack Exchange
I like to slice them about 1/4 inch thick and then drizzle with olive oil, fresh thyme, garlic, liberal salt and pepper.
Bake on a sheet tray lined with parchment or silpat, until they start to release a lot of that juice, drain that juice off (save for other uses or sauce!).
Then let cool before adding to pre-baked pizza (so they don't fall apart) with the other desired toppings.
As long as the pizza doesn't take longer than 30-45 minutes they shouldn't brown too much, and you will get a more intense tomato flavor with your slices.
cooking.stackexchange.com/users/2052/Avery Wittkamp
Whenever I make a pizza with fresh tomatoes on it, the juice from the tomatoes turns the crust to mush.  I think I must be doing something wrong - do I need to pre-cook the tomatoes to get rid of excess juice? Or maybe pre-cook the crust instead?  Is there any way to keep pizza from getting soggy when using fresh tomatoes, or is this just a problem with using fresh tomatoes as toppings on pizza, and there is no way to prevent it?
Keeping pizza crust from getting soggy from fresh tomatoes
cooking.stackexchange.com
<pizza><tomatoes><fresh>
cooking.stackexchange.com/questions/5728
cooking.stackexchange.com/users/337/Keithius
Make sure the dough is stretched evenly and precook it for a few minutes first. Brush a thin layer of olive oil on the dough before adding toppings, or add tomatoes immediately after cooking the pizza. Start by brushing the crust with olive oil. Then you can pre-cook the crust before adding toppings. For fresh tomatoes, add them just as the pizza comes out of the oven.
Brush your crust with olive oil before adding the toppings. Make sure your dough is not too thin. Pre-cook it so it is already slightly crispy. With fresh tomatoes, put them on just as the pizza comes out of the oven.