It takes time to cold call and door knock to find deals.

how should I approach door knocking my preforclosure list? 

I have an occasional headache as I am sure everyone does, but so far (knock on wood) my tenants pay on time every month are not too demanding and take care of the place.

I had previously knocked on their door twice to offer because I have a truck and live in an area with free brush recycling but no answer.

They are probably not going to understand a real estate contract on their best day, let alone when a wholesaler comes knocking.

@Omar Khan knocked it out of the park. 

I hope you knock this out of the park.

Conventional financing usually limits seller credit to 2 percent or less of sales price.The other option is to just knock 10k off the purchase price but then you need 10k or more in cash lying around.

You can find places like that by paying for lists from a place like listsource and doing direct mail or by driving around and knocking on doors.Even if they want higher than you can afford with your $20k you might be able to get into it with owner financing.In any case, just start doing these things.

I did mine online and knocked it out in 30 days.