I’ve been analyzing airfares and hotel rates for most of my working life. (Sad, right?) But at least I’ve learned a thing or two — or three.

Here’s my most up-to-date advice.

If the price of the cheapest one-way ticket is half the price of the cheapest round-trip ticket, then buy one-ways, and do so on different airlines if it’s cheaper (American outbound, United inbound for example). Here’s why: If you buy a $200 round-trip from LA to Vegas and need to change just the outbound flight, you’re out the full $200 (those hated airline fees). Buy the trip as two $100 one-ways, however, and you’ll lose just $100. I always buy one-ways except on those international airlines that only sell round-trips at the lowest fares.

If searching flights for two or more passengers, try pricing one passenger at a time. If there’s only one seat at the lowest price the airline will price both seats at the next highest fare.

If you’re booking a flight on an airline to Europe that is cash-strapped — usually the ones with the lowest fares (R.I.P. Primera, Air Berlin, WOW) — only buy with a credit (not a debit) card 60 or fewer days before travel. If the airline goes belly up, your credit card company must eat the charges (federal consumer protection rules apply).

Check to see if more than one airline is selling seats on the same flight. That’s a code share in airlinese. I recently reserved a premium economy seat to London on British Airways but I bought it from BA’s code-share partner, American Airlines, on its website for hundreds less than it was listed on BA. Plus, American let me reserve a seat at time of booking for free; BA charges $60 or $70 for seat selection until 24 hours before departure.

Beware travel sites that don’t have all airlines. Southwest only lists its fares at Southwest.com, so always check the site to see if they’re flying where you want to go.

Delta has pulled its fares from some fairly popular apps like Hopper. How to tell? Do a sample search from NYC to Atlanta, a Delta hub. If the site or app doesn’t show any Delta results, you’re not getting the full picture. (I think apps and sites should disclose which airlines they don’t show, but that will never happen.) There are rumors that United might pull fares from some third-party apps and sites, but so far it’s just travel industry chatter.

For a starting point when searching airfares, I do like Google Flights even though the search-engine giant has became heavy-handed, shoving its own travel products and other offerings down our throats whenever we do a search — it’s not for nothing that they’re under antitrust watchdog scrutiny. Like most Google products, it’s a bit nerdy and more complicated than it needs to be, especially with a recent redesign.

My favorite feature of Google Flights, though, is the fare map — if price is more important than destination. Instead of entering a specific destination airport, click on the “Explore destinations” link below the main search bar and it will spit out which places have the most affordable flights for the dates or time frame input. The “date grid” and “price graph” features are also useful for finding fares if you’re date-flexible and willing to fly whenever fares are cheapest. It also shows alternative nearby airports (Newark vs. JFK vs. LaGuardia). It’s a bit “inside baseball” and takes some exploring and patience, but they’re a useful set of tools.

That said, Priceline might have a fare to, say, Italy that is hundreds less than on Google Flights. That’s because online travel agencies buy seats in bulk and sell them on sites like Priceline — either as part of air+hotel packages or airfare-only.

Traveling solo? Some top hotels, such as the delightful Lygon Arms (above), an old coaching inn in the English Cotswolds, and London’s adorable Draycott Hotel, have single-bedded rooms that are much cheaper than, but just as luxurious as, the larger ones. But you won’t find them for sale unless you specify one guest. (Booking sites always default to two guests, you may have noticed.)

Don’t be afraid of booking hotels via websites you’ve never heard of. I booked a room at the Fairmont Copley Plaza in Boston last year using one of ’em — I’ve even forgotten the name … HotelWow? HotelNow? — and saved $250 compared to the hotel’s website. (Again, only use credit card to pay. Also, Call the hotel to make sure your room is booked, and finish your stay within 60 days of the charge appearing on your credit card statement.) Lesson: it’s not always cheaper to book directly with the airline or hotel.

I always look at the hotel’s site and then compare its rates to what I find on Trivago. Trivago list prices on some little-known vendors — that’s where I found the Fairmont deal– as well as on Priceline, Expedia and other online travel agencies.

If I can’t find a deal online, I’ll call the hotel’s reservations manager directly (not the 800 number) and try to finagle at least free parking or free breakfast. Sometimes there are special deals lurking in the hotel’s computer systems that you won’t find online.

George Hobica is the founder of Airfare Watchdog. For more tips and low fares, follow him on Twitter @airfarewatchdog.