How to market Real Estate properties online?

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I've been working in a real estate investor, He asked me to market his property.. What I did is facebook marketing, Twitter and posting ads on craigslist, postlets and backpage. Ive been posting in olx, it says my ad is live but when I checked it i can't find it. I also wanted to know what are some free US ads in US where I can post real estate ads or find buyers and sellers. I've been joining to realestateinvestor.com forum too but I need more info in real estate marketing. Can anyone help me with this? Thanks!