DIET: Yeah, make sure you know the diet well and stick to ReptoMin or BioRept most of the time, but juveniles are carnivores so feed them cooked chicken, a little raw meat, worms, and fish.
SAFETY: Watch water temps, get basking lights and make a basking spot; be sure of tank safety, ie., watch out for rocks that slide and trap the turtles, not too tiny of gravel at the bottom; don't put in the sun in plastic containers; no raw chicken or pork; and get a strong filter but one that's safe for them.
You learn as you go along but I've lost a few without knowing these safety tips.
If a turtle's sick, separate it. And a good website to help all your needs is turtleforum.com.