The can also assess the rental rate and vacancy rate of the area (after you find a property)  If you are waiting for an agent to bring you properties, when they have other clients they are working with and other agents can easily see these listings too, they wont be the good deals.Good deals are found by networking, driving around, scouring the notice of default and foreclosure listings, etc.   

Find a market you like and BUY something that will provide decent returns and grow organically.

Remember a 1% appreciation in your property is actually multiple times more return for you depending on how much you put down.

If you are looking for 100% financing start to build an army of private investors looking for a return on their money.

In return, I get to live in one of the units for free.

to get the highest return.

I really want to take a loan against my rental building so I can buy more investment properties, but my situation is I don't have tax returns ( new immigrant and this property has only generated income for 6 months), any suggestion on which financial institution can help a case like mine?

Stated income lenders do not take in to consideration tax returns or verify incomeRates are slightly higher but not as high as HML

How'd the return numbers turn out compared to your projections?

One offer with conventional financing and another higher offer with seller financing.This way he looks at the higher dollar figure and is more appealed to that offer.As suggested - it also helps to provide pros/cons for the seller to do seller financing.He might find it attractive if he is nearing retirement and still looking for an attractive rate of return via the interest rate on the seller financed note.