If you do decide to do mailer(s), then I would advise you to personalize the card and do a handwritten note. 

Funny you mention the whole GP / LP thing - I spoke to someone recently who claimed to have raised $10M+ for a fund and owned over 100 units.

Some will be ok in 2nd position and some will not and force you to refinance out the first - but those are options that are probably cheaper than credit cards 

It feels very difficult to raise enough capital to get into the market.

Also putting a business card and flyer on the door could work.

One of my clients had a $1M deal under contract where they needed to do a $300k raise. 

File lien if you find assets. (3) File wage and bank garnishment if you have bank account number and current employer. (4) In most cases it is impossible to find current whereabouts of the tenant to serve any papers (garnishment papers)(5) We have started asking for car insurance cards to get information on the car, the only asset most tenants posses.(6) We have not been able to find new address of any of the evicted tenants.

But even to this day the money is always the winner not me.. thats how you raise significant capital ..

Raising the rents will not be as easy as merely sending out notices of rent increases.

.* Additional Charges: Jenny requested that I deposit on her checking account an additional $20-25k for her to purchase furniture, which I refused because I thought it was very strange, opting to give my card # instead.* Work Quality: Jenny never showed up to the house, she sent 2 people instead, she never mentioned she would not show up herself, she never asked for approval to send two others instead, they did not complete the job, and there were multiple unauthorized charges on my card.* Receipts and Expenses: Once I brought to Jenny's attention that we were 20k above budget, she refused for days to give me the receipts, saying that I needed to give her my credit card statement first.