The West Sussex airport, south of London, said it has hired 400 new security staff in recent weeks to help ease queues.
Bosses said more staff are being recruited in a move aimed at reducing pressure on the airport as it goes into the busy English school summer holiday period next week.
Gatwick, Britain's second-busiest airport, is also trying to increase awareness about placing liquids in a clear bag, separate from hand luggage, to reduce delays at security.
Chief operating officer Adrian Witherow said: “With passenger numbers rapidly returning to 2019 levels, we expect to be busy, particularly at peak times such as weekends and the forthcoming school summer holidays.
“We are doing everything possible to make the airport process as smooth as possible, including recruiting and training hundreds of new security staff, many of whom have already started or will be in coming weeks.
“It’s also important, however, that we do what we can to help passengers prepare for security before reaching the trays.
“We understand many already do this, but, by publishing the list of top items that are currently being forgotten, we hope to get even more people through airport security quickly, so they can go on and relax before their flight, enjoy a drink or sit down for a meal.”
The announcement comes amid an air travel crisis which has seen thousands of flights cancelled and many passengers forced to wait for several hours in queues.
Passengers have also been left without their luggage, due to shortages of baggage handlers.
Travel chaos at UK airports – in pictures
Heathrow, the UK’s busiest airport, recently introduced a cap of 100,000 daily departing passengers until September 11, and pleaded with carriers to stop selling summer tickets.
However, The Telegraph reported that it has seen a letter from Mark Powell, Heathrow’s director of operational planning, which said a cap of 1,200 aircraft arriving and departing per day could last until October 29.
Many passengers at Heathrow have suffered severe disruption in recent months, with long security queues and baggage system breakdowns.
Staffing for ground handling teams at Heathrow are only at 70 per cent of pre-pandemic levels, whereas passenger numbers are at 80 per cent to 85 per cent.
Heathrow chairman Lord Paul Deighton this week blamed “slasher” airlines for failing to recruit enough staff to cope with passenger demand.
EasyJet announced this week that it has recruited 350 new customer service staff and is opening a new call centre in Milan to help ease delays.
The airline will also be stationing head office staff in UK airports to provide additional support to passengers, and has introduced new interactive signage in airports.
It will also allow customers travelling on early-morning flights to drop hold baggage off the evening before they travel.
Chief executive Johan Lundgren said the low-cost airline had stabilised it flight operations after cutting its summer schedule last month, but melting runways and air traffic control restrictions were not helping during a “challenging summer”.
He said easyJet's daily operations were back to pre-pandemic levels after the cuts, which followed caps on capacity at Gatwick and Amsterdam Airport Schiphol.
“We can't help if runways are closed down because they're melting, we have help if air traffic control puts restrictions into the flow system,” Mr Lundgren said at the Farnborough International Airshow on Tuesday.
“But the things that actually are within our control, that's been stabilised.”