Using IRA to defer taxable passive income.

I own one apartment which is netting about 7k per year income. I also am not able to itemize right now since I don't own my own primary residence. I do not have a lot of deductions in other areas. I'd like to postpone paying taxes on this passive income. 

I already max out my 401k at work, and I am considering very early retirement so eventually the funds will be roth pipelined into living expenses. 

I'm wondering what the experienced full time passive investors with minimal to no earned income do for their retirement planning. Other than more acquisitions of course.