Clarifications on hiding and stealth

Hiding and Stealth mechanics are poorly described and many people have made their own variations. One point that is repeatedly made and can be very valuable to the discussion is that a round is very short and an attention span of any creature is generally long enough to track a creature with whom they are engaged in combat.
  Simply put, this means that if a rogue were to move, hide (bonus action), shoot, the enemy would expect the shot to come from that location and the roll would not gain advantage. If the rogue were to hide, move, shoot, then it would work. As long as there is enough movement after becoming hidden it is all fine.
 

Hiding

Hiding according to the SRD:
"The GM decides when circumstances are appropriate for hiding. When you try to hide, make a Dexterity (Stealth) check. Until you are discovered or you stop hiding, that check's total is contested by the Wisdom (Perception) check of any creature that actively searches for signs of your presence.
  You can't hide from a creature that can see you clearly, and you give away your position if you make noise, such as shouting a warning or knocking over a vase." See: SRD:Dexterity#Hiding
 

What is appropriate for hiding?

Visually:

The target's vision must be heavily obscured (lightly for wood elves). This means blocked by environment, in darkness, or camouflaged. So if you are hiding behind a houseplant in broad daylight it might not be enough to hide, but if it is in dimlight it would likely be enough. Note that dimlight is as perceived by whoever you are hiding from.
 

Auditory:

You need to be quiet, especially if you try to be stealthy before combat starts. The combat rules don't specify any movement reductions from being stealthed but the travel rules state that you move at a slower speed, which is roughly half the normal speed. The argument here is that combat is noisy so most normal sounds will go unnoticed by most targets. This is also one of the reasons why the heavy armors give disadvantage on stealth checks, as they would just make too much noise. So as long as you are in combat, being stealth does not mean you need to slow down to stay quiet. If you are not in combat or if combat is relatively quiet for another reason you might need to check with the DM if you can move at full speed.
 

Olfactory:

There are few creatures for who this is significant. Snakes for example "taste" the air and can even detect the direction of whatever they tasted. Masking your scent, for example by covering yourself in mud would take more than 6 seconds, so it wouldn't work in combat.
 

Other:

Some creatures might be able to detect magic, either see or sense. This means any magic item might mess with your stealth.
 

What breaks stealth?

Getting in the target's field of view, attacking, spell casting, shouting, triggering a landmine, you know, most things.