What I would do is focus on marketing of my business to get the phone ringing more.  

If you say, as most do, "We Close Quick, All Cash Offer, Any Price, Any Condition" but in actuality you cannot do those things, then you are setting the wrong expectations before the phone ever rings.

Champion.

I use a local virtual number from Ring Central and think it's better unless youre branding your 1-800 number.

Is it okay to put a note on their door, ring their doorbell to introduce myself, etc.?

The house we have has exterior Ring cameras at the front doorbell, side gate, and backyard over the pool. 

Id like to ramp up the marketing machine get the phone ringing and start wholesaling and making 5 figures in 30-60days.

I really need to get this set up and going because as of right now i am only doing the bandit signs (which is a headache but get the phone ringing)  and driving for dollars.My next question is do you keep sending postcards and yellow letters to the same people everytime? 

Google voice is free and will ring to your cell phone

The phone began to ring; I went out immediately to talk with potential sellers.