Here, I prepared a list of tips you can do/follow to optimise your storage space.
It is better to spend a little more on packing materials like boxes or pods when organising your stuff to be stored. Piling boxes upwards is better than just putting or throwing everything in. You can also use your clear bins in storing your things as they allow you to keep track and see your items easier and faster without having to dig through them.
Spend a little more time and effort in sorting your things out. This way, you will be able to see and separate those you will need in the future and those that you won't. Donate or sell these unnecessary things --- don't let them take space.
Furniture like chairs, tables or cabinets takes up so much space, so it's better to disassemble them before storing. Put them in a box and voila --- you save a lot of space, making room for other stuff you wish to store away.
For easy tracking, keep an inventory or list of things you store and where you place them. It doesn't have to be complicated. Just list down and put the location. Number or label the boxes where you put your stuff for your reference. Simple, isn't it? This will help you track your things when you need them. You don't have to dig in every box. You can also create a simple map to summarise the location of your stuff in the storage unit. For example, a quadrant map --- divide your stuff into four different categories. Place each category in each quadrant (section).
Keep the stuff you visit/frequently access towards the front so you won't have to go through the storage unit to find something, turning it upside-down. And make sure to leave a space inside the unit where you can sit while browsing through your boxes or bins and where you can access your things placed on both sides and at the back.