Skills

I am so very lame and have never maxed out a skill for my sims before.

Photography...

Photography and painting.

Martial Arts and handiness.

Gardening, cooking and alchemy.

Like cooking, there are some skills that I too like to max out. Now, this is not the case for every sim, but only a certain type of sim, such as the one I'm playing now. The sim I'm playing now started out as human and has an LW wish to get to the top of the Law Enforcement Career. She basically loves to learn as much as she can. As a result, she found a way to become a witch. With this type of sim, these are the skills that I love to max out;
Alchemy
Cooking
Gardening - well at least up to 7
Spell Casting (hidden)
Science - this way she can clone the creatures instead of killing them for her potions

If I'm just playing your regular everyday sim then it would only be
Cooking, and Gardening They kind of go hand in hand.

Painting

So many to choose from. The following are essential and all are hidden skills.

Bowling
Darts
Pinball
Skee Ball
Video Games
Shuffleboard
Foosball
Pool (Billiards, not the swimming kind)
Table Tennis

Are any others really required? Charisma maybe, not hidden, but it just sort of happens by itself once my sims get past the Level 1 hurdle.

I like having my SS doing painting as I like to be artistic in rl even though I don't really paint myself but do love crafts and such. So now my SS has maxed out her painting and trying to work on her photography skill... :)

Cooking and Handiness... I designate a sim or two to these skills so they can keep leftovers stocked and repair/upgrade objects for the household.

Sometimes I have live-in help not related to the family. Often helping out as a nanny and/or gardener too.
https://66.media.tumblr.com/0a175003757916ffd5a4048f46906044/tumblr_p86jnjMSDY1ssiu0eo1_1280.png

I have my sims learning skills online from smart phones,computers and iPads as they often have all of the above and I use a Mod to make that option available from MTS.I have sims who master most skills and some who might not be nearly as skilled because they focus on other things more and I play my entire towns.

Cooking, fishing and gardening are the main ones for me although they do max other skills depending on their LTW or personalities during their lives.