I am not an expert on the selling side as far as an agent is concerned, but I can try to at least give ideas. One thing I've noticed is that the turnover rate within the first year for RE agents is very high. This was the same way for me when I did outside sales.
-It really took about 10-12 months for me to get traction and get my name out. I feel this is the same for RE agents, just keep at it.
-Personally the agents in my area don't do much direct mailing, but have a great social media presence and everybody knows their name. Instead of time and money on direct mail, maybe think about sponsored posts online and signs.
-You are active on BiggerPockets and investors buy more and more often. This may be a great tool.
-You're in an active market in Columbus (I imagine) so I would focus more on just finding sellers. Buyers may take forever to find a home even in slow markets. This will also accomplish points one and two of getting your name out.
-Be honest and don't go crazy trying to oversell anything. I can't speak for everybody but I can certainly sniff this out. The agent I ended up listing my recent renovation with was the one who didn't come in and go "oh this is beautiful what do you want to list it for? XYZ price okay great lets do it!" He came in and said "honestly I would fix this, this, and change this, and I think we should list it closer to this and that it will ultimately sell for this." He was within $3,000 of the final sales price and it sold to the second viewer in my market which is very over saturated and slow moving.