Your children could have many bikes and the problem is that these kind of things take a lot of space. However, there is a solution to this problem. You can hang them on your walls to help make your garage clean and spacious.
In any case, when you organize it is important to know that you have to group things that are alike together. You can arrange them and label them to help you know where they are placed if you need them in the future.
Your walls could have studs. This can be a great way of innovating storage places for all your stuff. Just like in the picture, you can practice your creativity in organizing your garage items.