Aquariums - Flash or No Flash?
Using a flash at an aquarium equals all reflection and no fish. Sure, unless the interior of the aquarium is lit well (most aren'd due to visibility through the aquarium glass) or you brought your entire external lighting set up with you, you wont be able to get a well lit shot of both the fish and your child. But what it does do is make for some pretty good silhouettes.
Sea Base at EpcotWhat if it's too bright outside?

When you’re on vacation, you might be sightseeing in the middle of the day when the sun is at it’s brightest. What do you do then? Avoid a great picture? No way! You look for open shade.
Open shade is an area that’s shaded from direct sunlight but is still illuminated by reflected light. For example, if your subject is standing in the shade of a building or big tree (facing away from the building or tree) that’s open shade. If there’s a white or neutral-colored wall, road, sidewalk, etc. near your open shade, that’s even better! It will act as a natural reflector and bounce light onto your subject, giving them beautiful radiance and nice catchlights in their eyes.

Clouds. Natures Diffuser.
Pray for clouds. They’re like a giant version of those silver umbrellas you see at fashion shoots: Everything comes out evenly lighted, especially portraits

Blurred and strangely lit night shots?
There's a lot of ways to get those night shots without the blur or really blown out portions of the photo. One of the things that I find helpful on the iPhone is the able to adjust the exposure before taking the photo.Tap the object you want in focus, then look for a little box to pop up. Slide your finger up and down to make the shot brighter or darker. It won't solve all of your problems but it helps.

You don't have to be the only photographer
Giving everyone a camera is a great way to really integrate photography into the trip and help ensure your kids don't get bored looking at mountains when they'd rather be riding roller coasters.

It doesn't have to be anything expensive, anything from a simple $10 drugstore flash and trash to something in the $100-200 range will get the job done. You'll be surprised at how many really great shots will result when you give a kid a camera. Just don't be upset when you realize your six year old takes better photos than you! If you want the best photography read this.
