The best tip I can give you is to start off with at least a 20 gallon long tank, even better a 40 gallon long. These turtles require exercise, and room to grow. They grow rapidly. Within one year it will be best off in a tank larger than a 20, with about 75 to 85 percent of it water space, the remainder a basking area. I imagine a small adult could get away with remaining in a 40 gallon long, so long as it could get out into a larger tub for exercise often, but a tank twice that size would be much better; while one around 100 gallons would be considred minimal by others. Of course, you can use a ten gallon tank, but it will have to be changed by a year's end at most, maybe sooner.
A submersible filter is a good thing, as would be a submersible heater. Any power filter than circulates the water through a filter medium should do ok. The thing is though that if you have one hanging from the edge of the tank, the water level and dry areas may be so high that the turtle can get up on the dry area and climb out. Make sure to cover the top with a screen of some sort. This is a good platform for the lights and prevents escapes. People are often amazed that they find their turtle in a corner covered by a dust ball, anmd wonder: How did it escape! They can climb surprisingly well and if given a foot hold they will escape. A heat lamp and a reptile UVB bulb should be used over the basking area. If you use a rock for the basking area, make sure it is smooth. Too rough a surface will possibly scratch the plastron.
These guys should get a large variety of live animal foods and plant material. Goldfish, guppies, earthworms, turtle pellets, water plants, green leaf lettuce usually are all welcome foodstuffs.
A few times out in the sun each week during nice weather is also a good thing. Care must be taken to provide both sunny and shady areas so the turtle does not overheat. A couple to a few hours a day of this, two or three times a week is great.
