Here is the advice I always give travelers, especially on my small group tours, on how to get through airport security quickly:

Plastic Bags:  Anything and everything that could possibly be flagged on the x-ray machines goes in zip-lock plastic bags.  I even put the stuff in smaller zip-lock bags in larger zip-lock bags.  Eyeglasses, scissors, liquid containers, coins, electronics, cords and wires, phones, pens, razors, anything metal or liquid.  I then put my big plastic bag in the container for scanning.  That way, if anything is flagged, they only have to look in one place instead of having me unpack my backpack or carry-on, a time-consuming and aggravating process.  In airports like London (LHR) they will make you empty out your entire bag if they suspect one little thing in it.  But if everything is in an easily removable plastic bag, that's all they will check.

Enroll in TSA Pre-Check:  This has saved me as much as an hour waiting in line at airport security.

Enroll in an Airline Elite Status Program:  Many of them provide travelers with an expedited security line.

Fly Out of a Smaller Airport:  Big airports like JFK, LHR, LAX, ATL, ORD can have enormous lines.  If I can, I fly out of my local airport at Hartford (BDL) or airports like Chattanooga (CHA) or Islip, NY (ISP).  Sometimes there are NO security lines there at all.

Always Cooperate:  I know it is a hassle and sometimes TSA agents can be annoying to deal with.  However, if your objective is to get through security quickly, just smile and comply, saying as little as possible.  Arguing will get you nowhere but spending more time at security.

Don't Say Anything Suspicious:  Don't talk about threats, weapons, what's legal or illegal to carry on.  Joking about security is no joke - it could cost you being delayed for an extensive period of time.