If I am listing a unit for rent I will be inclined to advertise in English and probably Spanish as well. 

There has been no advertisement so far, and I talked directly with the constructor about the prices.

Essentially you need to understand the ROI associated with real estate (and Ideally investing in general) and how cap rates, equity, appreciation, and liquidity all play different roles.   ..and when you advertise your properties be sure to quote the most accurate numbers you can.  

For every 20 leads we get (callers that respond to our advertising), we schedule 8 appointments and get 1 purchase contract.  

Sorry @Michael Egan, I tried to give you, and all others watching this post, a leg up by giving you exact direction for Step 1, the most critical step, in building a pipeline of off-market deals and some Moderator banned and removed my post saying I was "advertising my company" even though I don't own it, it's been mentioned about a bajillion times by thousands of others, but ok, apparently I can't mention them.

What has worked well for me is to advertise everywhere ..facebook and every site I can do for free and then do an open house for all the interested people ...one during the evenings on a week day and then another on the weekends to show to any of the interested people. 

What you need to try to avoid is being advertising for a broker but really DO know that from the second they take that listing for lease or for sale, they are out of pocket for your asset and have lost money unitl it leases or sells.

We advertise the units exclusively to traveling nurses on 2-3 month stays and have had really good success. 

It's just a commercial/advertisement (cheesy one at that). 

I have nothing other than leases from other houses and the current listing/advertisement as proof that I require a pet fee.