Opinions on taking out a loan on a rental

[Chris C.]

i have a rental that is currently rented out by a metro tenant I own the house free and clear but by paying cash for everything I now am tied up for trying to get property number two, so my question is 

do you sit back and wait while collecting rent before going for the second house? 

Or do you take out equity on this property to pay for number two?

I've had a good friend suggest he just waited at first and worked his way up now he is doing very well but in my eyes I see house one paying the loan and covering number two without coming out of my pocket although I'm sure I'm missing something any opinions or some that have gone down this road before have any input thanks