This question depends on a number of things or characteristics of your team/s and your process.
1 The first question to ask yourself is if you want to work with one PractiTest project or with multiple PractiTest projects.
If you have a limited number of people and everyone is working on the same projects, you may want to work in 1 or a limited number of projects.
If you have separate teams working on separate assignments, with defined integration points, you may want to have each team and product family working in their separate PractiTest projects.
2 The second question is how to organize your data.
Sometimes you may want to organize your data based on products, other times releases, and at times based on other criteria like whether a test is a regression or a sanity test, etc. See the additional information here
Fortunately, with PractiTest you don't really need to choose one organization way against another, you can work with as many organization approaches as you wish using our Filter Tree approach. Find the additional information here