Depending on what type of trip you're going on, the planning process can feel overwhelming with so many pieces of the puzzle. You have to figure out the best time to go, get the best flight deals, figure out where to stay, what to do, and which apps are worth downloading. Look no further - here are the best online travel resources for planning your next trip:

Flights

Skyscanner

A website I've used for years, Skyscanner is like a flight search engine for all the flight search engines. It give you the lowest available price from various airlines and then breaks down the price differences from other websites to get you the best deal. You can also search flights from your destination to "Everwhere," which searches different countries around the world. I almost (but thought better of it due to other factors) bought a RT flight to Trinidad and Tobago through the Everywhere tool!

Kayak

I use both Kayak along with Skyscanner, mainly because of my favorite "Explore" tool as well as the "When to buy" graph. The explore tool shows various flight prices around the world from your airport. You can choose the time of year or specific dates to get an idea of how much flights will cost to different destinations around the world. I like this more than Skyscanner's "Everywhere" search option as this one has an interactive map. (Update: I was on Skyscanner and saw that they also have a new interactive map tool!)

The "when to buy" graph is especially helpful when debating whether or not to buy a flight based on the assumption that the price will fluctuate. Kayak has an algorithm that guesses if flight price changes will happen within the next week based on archived information. Take it with a grain of salt...this has both helped and hurt me by $100 each way on different occasions. Though I still feel like it's a helpful component of the website!

Read: Where To Find Cheap Flights

Some additional tips for finding good flights:

Airfare Watchdog and The Flight Deal are other good sites for finding rare and really cheap flight deals.
Setting up price alerts is another helpful way to gauge ticket fluctuations; Kayak and Skyscanner (among others) email you daily with price updates on a particular route.
Keep an eye out for additional fees on budget airlines - some charge extra for carry-on bags or only fly to out-of-the-way airports. Add up the extras to see if you're really getting a deal on the flight, or if you'd be better off on another airline.

Accommodation

All The Rooms

I just found out about this website more recently due to an Instagram collaboration and wish it existed when I studied abroad a few years back! All The Rooms is a search engine that takes into consideration not just hotels, but also alternative forms of accommodation like hostels, AirBnB, Couchsurfing, etc. So helpful for those studying abroad, backpacking, or simply looking for multiple options for accommodation when traveling.

Hostelworld

Hostelworld is a site I scoured when looking up hostels traveling around Europe (though you can look up cities anywhere around the world!). The reviews are especially important - a hostel may look great in their professional photos and have an awesome website, but if half the reviews say it's dirty, in a bad location, or not entirely safe, then you'll probably want to skip it.

Review Sites

I highly recommend reading reviews before you purchase something, especially if it's new to you! If you haven't used/don't know someone who has used a service personally, reading reviews is the next best "word of mouth" strategy. This has saved me a lot of headache over the past couple of years!

TripAdvisor

The travel review site of all travel review sites, there is no better one I've found than TripAdvisor. I check TripAdvisor for tips for things to do in cities I'm going to, real photos submitted by other travels, and by comparing reviews from people who have "been there, done that." I always check hotel reviews on TripAdvisor, as well as read forums on helpful topics, even for simple things - for example, what it's like to drive from Phoenix to San Diego and if there were any flood-watch areas. (There were, and I avoided that route because I was driving during Arizona's monsoon season!)

Yelp

Another review site that really needs no introduction due to its popularity, Yelp is one of the easiest ways to get recommendations on where to go based on your location. I've found it especially helpful for finding good restaurants, bars, and services (nail or hair salons). I also found some good insider tips on certain attractions while traveling with everything from bars in the "Bermuda Triangle" in Vienna, or a faster, easier Louvre entrance in Paris (hint: go to the underground entrance by the arch, not the glass pyramid entrance).

Blogs

Blogs (like this one!) have a ton of information on pretty much anything you can imagine. A quick Google search gets you links to information instantly, and someone's personal perspective on a topic will help you prepare for when you're actually there.

Blogs for:

Inspiration:Grease & Glamour

Travel Hacking & Budget Travel:Nomadic Matt and Chris Guillebeau

Millenial Travel:TravelBreak

Southeast Asia travel:Christian Leblanc (Youtube)

Central Asia travel:Heart My Backpack

South America travel:Hey Nadine (she goes all over too!)

Central America travel:The Blonde Abroad

Study abroad:The College Tourist and Go Seek Explore's Study Abroad tab ;)

Working abroad:Wandering Earl and Go Seek Explore's Travel After College tab

Family travel:Y Travel Blog

This is by no means an end-all-be-all list for helpful travel blogs, as there are SO many good ones out there! Also, not all the blogs mentioned are completely region- or topic-specific, and have tons of additional info as well.

Mobile Apps

I use all of these apps and have found them extremely helpful when traveling. Roadtrippers showed me where the closest gas station was when my tank was getting dangerously low, TripIt keeps track of my flight codes/info so I don't have to... embrace the power of technology to make things easier on you!

Keeping track of your itinerary: TripIt
Road trip resources: Roadtrippers
Translating: World Lens or Google Translate
Learning languages: TripLingo
Exchange rates: XE Currency
VPN: SurfEasy, Hola (I hear TunnelBear is good too, but haven't personally used it)
Flights: Skyscanner, Kayak
Review sites: TripAdvisor, Yelp

I hope this helps you find some good resources when planning your next trips! Feel free to get in touch with me anytime if you need any travel tips, I love answering questions (or talking travel anytime, really).

Please feel free to add any additional websites, blogs, and apps you've found useful to the comments for travel planning!