Full storage is a challenge, but it is a great motivation to:
A) sell sell sell. Let go of the stuff you produce by selling it and keep the simoleans circulating. Save your space for things you have to collect for a while, like the items for expansion. It's easy to get in the habit of keeping a few if everything just in case you need it for construction or for a disaster challenge, but it's not worth the storage it takes. Keep cleaning the cupboards. You can always make it or buy it again when you need it.
B) Keep upgrading your storage capacity. It is worth it.
C). Buy absolutely everything you need that you can with simoleans, not with cash. That is nearly impossible in the first few levels when you have very little production capability, but once your factories are running regularly, you should almost never require cash for tangibles, other than adding a spot to a store production queue. Keep producing and selling to build up your simoleans, then use simoleans to buy anything you can't produce, like expansion and Vu items, or you just don't want to wait for, using simoleans at the trade HQ.
A lot of this game I think just requires patience, which I personally find hard sometimes. But if I really want an item I can't seem to get for a while because the production queue is long, or the item isn't popping up for sale, I try to look for a different project to work on in my little sim land for a while. Eventually it comes to me.
