I have 4 houses - but what's next?

[Mark Oliver]

I rent out 3 homes and live in one. They are all single-family homes. I'm pulling in around $2000+ per month in net profits (after all expenses). What's my next step? How do I make the jump to buying bigger units (e.g. apartment complexes) or more SFH's? I've run out of money for down payments. Ideally, I'd like to make around $10k per month in net profits. What's your advice?