SRD:Miscellaneous Actions

Take 5-Foot Step
You can move 5 feet in any round when you don’t perform any other kind of movement. Taking this 5-foot step never provokes an attack of opportunity. You can’t take more than one 5-foot step in a round, and you can’t take a 5-foot step in the same round when you move any distance.

You can take a 5-foot step before, during, or after your other actions in the round.

You can only take a 5-foot-step if your movement isn’t hampered by difficult terrain or darkness. Any creature with a speed of 5 feet or less can’t take a 5-foot step, since moving even 5 feet requires a move action for such a slow creature.

You may not take a 5-foot step using a form of movement for which you do not have a listed speed.

Use Feat
Certain feats let you take special actions in combat. Other feats do not require actions themselves, but they give you a bonus when attempting something you can already do. Some feats are not meant to be used within the framework of combat. The individual feat descriptions tell you what you need to know about them.

Use Skill
Most skill uses are standard actions, but some might be move actions, full-round actions, free actions, or something else entirely.

The individual skill descriptions tell you what sorts of actions are required to perform skills.