1) My experience I've had better luck with small home town banks and credit unions who know and use same appraisers. Also, regardless of any upgrades, my credit union lender disclosed to me they have to use the "market value" or purchase price of house for first 12 months so was pointless to redo another appraisal for first year.
2) After first year we ordered three appraisals for a blanket loan covering three houses. I asked to meet with appraiser and walk around to "get an idea of what process is like" to learn more. That's how I pitched it anyways. Simply small talked and was nice but not a kiss @$$. With basic repairs and some needed cap improvements my appraisals improved. A. purchase price 82k/appraisal price 107k, B. purchase price 25k/appraisal price 37k, C purchase price 46/appraisal price 46K (new property I was buying)
First of these properties came with a 20% DP at time of purchase before I blanket loaned all three into one loan. Property C being the new purchase. I was able to acquire the third house with just Equity from first two houses. Since then have bought two more using strong equity position.
3) Point is you have to buy at a discount from get go to improve later value quicker...depends also on appraiser. three appraisers may give three different prices but sure as hell don't hurt to show up and put a face to that paper they will be signing later.
4) DONT OVER REHAB...repair what has to be repaired to make livable and make it presentable. We all are guilty of doing too much sometimes. If you are buying and holding I like to make presentable and functional. I'm not living there just collecting rent checks.
5) I will literally knock on doors and call "for rent" signs or talk to neighbors standing outside to get an idea of what I can actually get for rent. I always use conservative numbers when doing my math. Any extra I make is just a bonus to me.
6) No education is free ;)