Make music that speaks for itself, and then post it with a message that gets people to click on it. People don't have the attention span that they used to, so getting them to even play your track in the first place is an art of its own. Having an interesting title and a graphic to go with it can help, but people still click on type beats so that may not even be necessary depending on who your target audience is. Speaking of target audiences, it helps to post in communities where you're more likely to find rappers looking for beats. If you only post on your personal Facebook or Instagram, you can't expect to be seen by people who are looking for beats.
That said, understand that the market for beats is flooded and will be for the foreseeable future now that everyone and their dog can download a DAW. Selling beats and "making it" without money or nepotism is largely about being seen by the right person at the right time, which makes consistency the most important factor. The more you post in as many relevant places as you can, the better your chances are of being seen by the right people.
