I am interested in driving for dollars (Wholesaling) and the way I usually find properties is by mailing the yellow letter to any vacant properties using my equity leads list).

Another thing you should have before you start is a loan letter from your lender to include a copy of it with your offers to prove to them that you can close that states how long it should take to close you loan and the maximum you qualified for.  

For example, I know of pockets where people are still pulling 7+ cap rates and cash on cash can be in the double digits.  

I give my tenants a letter stating it is their responsibility to get and maintain renters insurance.

There is also the "reputation" factor.Let me ask you, are you pre-approved and/or have money in the bank (real $$, not a letter from a transactional funding place) to close the deal on properties you offer on?

Scott's books on flipping and estimating rehab costs are also great sources of info.As far as wholesaling is concerned, Find out: Your target area; ALL costs of a mail campaign (list, letters, postcards, necessary office supplies, postage, etc); budget for 6 months-1year of mailings; develop scripts for prospective sellers (what to say to them); learn to track responses, follow-ups, conversion rates, overall campaign effectiveness, etc.Build your team; title company, RE attorney, cash buyers, closing agents, etc.Feel free to reach out if you need any info.

Wide variety of mail pieces, including various sizes of postcards and letters.

As long as the timeline for your closing on the 1031 and the 30 day closing requirement for a cash Hud purchase coincide ,you should be fineYou will need a proof of funds letter from your facilitator showing sufficient cash available to closeI would also check with the facilitator and the title company you choose and ask if any additional closing documents will need to be signed by HUD and get them approved in advance if necessary .  

That will allow you to know which postcard/letter campaign these people actually read to get them to call you (assuming you are trying different designs/calls to action).

I have sent out roughly 1,200 letters since attending that course to hopefully find some sellers motivated to sell a house, but so far i've not found much. just curious how others first flip was like?