The first part of helping your fifth grader with homework is to be sure he is organized. My children have an agenda that is provided to them by their school for recording their daily homework. If your child's school does not provide this, purchase a planner or small notebook where he can write down assignments. My middle schooler is able to access a classroom portal where the teacher posts homework assignments. We try not to rely on it because it does not teach him to be responsible for his assignments, but it is a nice back up. It is also useful when he misses school and we can check to see what he is missing. If your child falls behind on assignments, then when test-time comes, it will be even more difficult to be prepared.
Also be sure you keep a calendar with dates for practices, games, recitals, and other family activities at the ready. If there is a huge science project due on a Monday and you know you will be out of town the entire weekend before it's due, make sure it is done early. This will save you some late nights. There will be plenty of those in college, no need to do them now!
Now, once the work is written down, it has to make it home. Depending on what your school requires, you need to purchase some type of binder or accordion for keeping papers. We like to use something that has sections for each subject and one for homework. It provides a straight-forward way of organizing school work.