There are some things that may need to be stored: holiday decorations, seasonal equipment, hand-me-downs for the next kid, etc. Remember that, if you’re putting things into storage without analyzing its usefulness or purpose, you are just putting-off decision making.
Take the time now to make sure you only have what you want. And make sure that it’s stored in a way that will be easy to find in the future.
Keep similar things together, like all the stuff for swimming on one shelf. Take the time to go through your bags and take out the things you don’t want anymore. Most importantly, you will be able to find things easily and have more space.