Requested by @jiyngz​. A small list under the cut, using examples from my personal experience. I’m no authority on the matter, this is just what worked for me 😛

1) Picking your reference pics: if you’re a big stickler for accuracy, this’ll be an issue. I personally go for candid shots, and pics where the subject is wearing as little makeup as possible. The more angles the better. Stuff like staged lighting, Photoshop/filters abuse, people only showing their “one good side” in pictures, and makeup are all nice photography tricks that WILL throw you off. Angles matter, facial hair matters, age really matters.

2) Use custom sliders, they are made of magic and unicorns.

3) Use face sculpting blushes and makeup if necessary, they’re a huge help.

4) Use a base sim that seems close to what you want your final sim to look like – this will not always work out the way you thought it would and that’s fine. 

5) If you can’t quite get a feature to look right and you feel the sliders aren’t helping, try blending in a bit from a BG/default/non-default face template, it’s surprisingly helpful.

6) In my experience, sometimes, individual features may end up looking right, but the face as a whole looks a bit mask-like and unnatural. In that case, again, try to blend in a BG/default/non-default face template (this time the whole face, not just separate bits). My defaults help me a lot with softening out features and making faces feel a bit more proportionate.

7) Save often. It doesn’t only ensure that no changes are irreversible, but also resets the sliders, allowing you to play around with features some more.

8) Take a break if you need to. It took me forever to get certain sims looking the way I wanted them to. Take a break, do something else for a while or sleep on it, and try not to let frustration get to you. 

That’s pretty much it! Hope this helps!