Develop highly targeted manageable niche lists & market consistently to those list with personalized unique messages ( It's not "I BUY HOUSES FOR CASH", that isn't unique at all). I use direct mail & follow-up phone calls, text, email.
@Robert Nabong could not agree more with the advice to develop niche lists and hit them with a memorable and unique messages. As an example, I have a small list of about 40 properties in a very particular neighborhood in the Bay Area. These houses are all within walking distance of a certain coffee shop. For my third mailer to these homes, I plan on buying $5 gift cards to the coffee shop to include with the mailer - saying something along the lines of "thought you might enjoy a cup of coffee on me next time you check on your property" (for non-owner occupied).
The best way as a new investor is to not buy a huge list and overmarket. Find the houses or areas that you like and create a personal one-to-one letter that may connect with one on your list, all you can hope for from a first mailer. What everyone said about niche lists is absolutely spot on. Too many smaller investor try to do spray and pray, but that's not the best with smaller and newer budgets. Figure out what you want to target, build a list, create a compelling and connecting letter, mail it and make sure to answer your phone!