Here are some simple and useful tips for getting through airport security as quickly and simply as possible:
TSA Pre-Check: The lines are shorter and the security requirements are not as stringent. For example, no need to remove most items from your bags, including laptops, nor do shoes need to be removed. Here is some info on how to enroll in the TSA Pre-Check program: https://www.tsa.gov/precheck
Avoid LHR (London Heathrow) Airport: Experienced travelers will tell you that security is probably the most stringent at this and other London airports. It is so spread out into several terminals and lines can be so long, I will only fly through LHR if absolutely necessary and I have at least 2 hours budgeted between flights. There is nothing quick and simple about flying through LHR.
Prepare a "Clean" Bag and then a Smaller Bag with Items that Might be Called for Additional Screening: For example, in my larger suitcase, I don't put ANYTHING that could possibly be flagged for further screening. If large bags are flagged for screening, security officials may ask to unpack the ENTIRE bag, check it over carefully and then have YOU re-pack it. That can take a lot of time. In my smaller bag I have packed in easily removable plastic bags anything that can possibly be flagged for further screening (small scissors, electronics, wires, soap, foods, liquids, etc.). I easily remove these bags containing these items before putting them through the x-ray screener. So, if anything is flagged for further inspection, it can be done quickly. I also keep laptops and similar devices in my smaller bag.
Keep Watches, Glasses, Coins, and Other Small Metal Objects Separate: If wearing a heavy jacket, I put them in the jacket pockets and pass the jacket through the scanner. Otherwise, I have another plastic bag for them. Also, collecting multiple items in single clear plastic bags makes them easier to retrieve and reduces the chance of forgetting an item or two.
Slip On Shoes: They probably save 2 or 3 minutes in the security check process.