Well, I've seen many different guides to the "not even once" achievement/trophy, but most of them leave you with some very unpleasant results. So, I thought I'd put out a list of choices that will allow you to get the achievement while maintaining mostly positive outcomes.

The most important thing to remember is that you cannot "EMBRACE" any named NPCs at all. With that off the table, your only options are to spare, charm, or turn the "pillars of the community" when the opportunity arises.

The choices with the most positive results are as follows:

SPARE: Dorothy Crane
TURN: Sean Hampton
CHARM: Aloysius Dawson
SPARE: Dr. Swansea

Besides the Pillars, there are 3 other moments where you're faced with options. The 1st occurs right after you reach Pembroke Hospital. Another is presented during a battle & isn't available through dialogue. The last is presented after a battle & resembles the choices offered with the pillars.
[Spoilers ahead]

1st choice:
After you save Sean Hampton & complete your boat ride to Pembroke, you are presented your 1st opportunity to memorize an NPC & feed. Instead of embracing him when the prompt appears, RELEASE him. You'll pick up a separate achievement for doing so.

2nd choice:
During your fight with Marry, let her feed on the priest. It will make the fight longer, but it ensures you are not responsible for the priests death.

3rd choice:
After your fight with Geoffrey McCullum, you can choose to SPARE or TURN him. The results are the same, but if you're looking for the complete "Hero" experience, SPARE him.

[Tips]
My advice for progressing with out feeding, pick 1 skill from each category & an ultimate than max your attack skill, ultimate & heal. Save your weapon parts & max out damage on a high end gun & any 2 handed weapon with parry. Invest in or max out blood gain, bite damage, & bullets. Carry 4-5 syringes & pick up some extra stamina & health.

Find & complete every investigation & cure every disease when they come up. If you need a little extra xp, sleep for a day or 2 until sickness spreads, than go out & cure it.

Use your attack skills regularly & take time to practice combat, dodge is your friend, use it. Don't be afraid to dodge diagonaly past them. Dodges flow comfortably into & after attacks.
(Skill, Dodge attack, attack, dodge, dodge attack, skill, attack, dodge dodge.)