1. Book early. Google sez: "According to a 2023 study by CheapAir.com, flights are usually cheapest when booked between 1.5 and 5.5 months before departure. NerdWallet recommends booking domestic flights 1–3 months in advance, and international flights 2–8 months in advance. Expedia says that booking 28 days in advance for domestic flights and 60 days in advance for international flights can save you 24% and 10%, respectively."
2. Fly off-season. The Caribbean is much cheaper in the spring than at Christmas or January. Generally speaking, "off-season" means before Memorial Day and after Labor Day.
3. Do the math. If you spend $200 on gas (RT) to save $50 on a ticket, you're doing it wrong.
4. All airlines offer deals (but usually not to where you really want to go). Check their website. And buy directly from them instead of going through an aggregator. They'll make sure you have reasonable connections, etc. Also, shop their bundles. You can save bucks on hotels and cars along with your ticket if you can buy all three from the same airline.
5. Take the red-eyes. Leaving DSM at 6 a.m. and flying back at 11:00 p.m. costs less than a flight during the "normal" part of the day. Actual example: If I want to fly Contour Airlines from Kirksville, MO to Chicago on June 6th, the 7:20 departure will cost $129, but if I wait until the 2:05 departure, I pay $94.
6. Pack light and take the cheap options where you get one carry-on, period. On United, a basic economy ticket from DSM to Denver is $203 RT. The fully-refundable ticket is $312. The folks up front are paying $442 for the exact same ticket, but they get the thrill of arriving first to the same destination.
7. Off-brand airlines are generally cheaper, but there's a catch. Once flew one of those cheapo European airlines from Seville to Brussels, and the seats were made out of hard, orange plastic, sort of like the ones that used to be in middle school classrooms. I kid you not.
8. Do consider using a travel agent. A real one. Not somebody who just sells Diznee cruises. I think we pay ours about $100 a trip, but he takes care of absolutely everything, transfers, hotels, etc., AND, if there's any kind of hitch, he does all the legwork and re-bookings. All I have to do is call. Pays for itself by saving time and aggravation. Peace of mind is worth something. At least, to me.