Classes
Class is usually the anchor choice of the build. It tells you what the character is meant to do under pressure, which abilities actually matter, what equipment makes sense, and how the rest of the sheet should support that plan.
Primary ability dependence. Know which score or scores the class actually needs before assigning the rest of the build.
Armor, weapons, and tools. Class proficiencies often determine what a starting loadout should look like.
Spellcasting expectations. If the class casts, that will influence feat choices, gear, survivability, and later progression from the beginning.
Combat Loop
What does this class normally do when initiative starts: attack, control space, protect allies, cast, heal, scout, or burst damage?
Exploration Value
Which proficiencies, spells, tools, senses, or mobility options help the party outside direct combat?
Social Footprint
Does the class naturally imply authority, mystery, training, divine service, criminal skill, scholarship, or public reputation?