As @Argenti Apparatus said, it is crucial for tires and tubes to keep them inflated.
Additionally, if you cannot hang it, at least change the tire - floor contact point by rolling the wheel.
Protect rubber parts from the sun - keep the bike in the shade or cover it. You can also spray it with i.e. silicone compound for rubber parts.
Clean and grease your chain. There is often enough humidity in the air to make not oiled chain to corrode.
Make sure that bearings are greased. If not - repack and grease.
I would personally oil brake and shifting cables.
Use proper bike lock or even thick chain that you would not normally use and check periodically against theft issues.