We all know what that means or most of us do. This page is comprised of exactly what the title says; how to identify what type of lag you're experiencing and how to fix and or prevent it. As well as some additional information.
First off though lets go over some common terms which can fall or are associated with this under this category: Delay, FPS (frames per second), TPS (ticks per second), ADD MORE IF U THINK OF THEM :)
Identifying lag: The first thing you should do when you believe you are experiencing lag is type /tps (this command will show the tps in the form of 3 numbers ranging from 0-20 from the last 1, 5 and 10 minutes respectively), if the first number is below 15
(^^^This will explain what methods can be used to figure out what kind of lag is affecting you^^^)
Fixing lag: First things first, saying lag in chat WILL NOT fix it. Now how to fix it....
(^^^this will explain methods that a 'player' can take to deal with lag and or remove it^^^)
Types of lag: Edit
Server Wide lag: This type of lag affects the entire server which means everyone on it is also suffering.
Block lag: You break a block and it doesn't break... at least for a few seconds.
Client lag: This is a very vague 'definition' of one type as many things can cause this... and by many I mean lots and lots.
If there are other type of lag feel free to add them, NOTE: if u can think of specific 'types' of lag instead of 'client lag' please add them.