East or West is the best way to go, though North or South can work too. If you go East or West, the advantage is there are often some Mistlands that are adjoining Black Forests on the same island, which makes for a much safer entry into the Mistlands than a water landing.
Look for large Mistlands areas for exploring. The first Mistlands you hit will likely be small islands. These often don't have several of the things you need to find in the Mistlands, so better to move on and find a large patch. By large, I mean several thousand feet of shoreline or more, not a 100ft wide island.
As others pointed out, the giveaway that its Mistlands when looking at land from afar is the jagged terrain. When you get close, much of it will be wreathed in an impenetrable gray-blue fog all the time. This fog is noticeably different than the regular white fog one encounters from time to time.
Also, when you do find the Mistlands, keep an eye out for the areas that have little or no mistlands fog. In spots there will at times be "corridors" of non-mist areas, which helps greatly in moving along and finding stuff. And opponents are less likely to jump out of the mist.
Before going, craft a Wisplight (and some backups) before going in. Use the Yagluth drop to make the device that gets you the wisps you need for a Wisplight. Also, bring a Black Metal Axe. You will need it for the trees in the Mistlands to harvest materials. And definitely bring a portal and set it up in a protected location away from the Mistlands a bit (like in a Black Forest).

Have fun. And be cautious. Going into the Mistlands for the first time is like going into the Swamp for the first time. Everything is nasty and one can die very fast. Take it slow and cautiously until you get a better feel for it.

Originally posted by Frank Dunn:

Just head east or west, should find it soon.

this. dead east or west from center (spawn) and you're there

the fastest way would to use this, just put your seed in and it will generate your world and show you where everything is https://valheim-map.world/?seed=ze7TiZpfAK&offset=-260%2C856&zoom=0.896&view=0&ver=0.212.7

i found one. its small but the fog tip helped a lot ty. Whats a good early way of dealing with the fog?

Early? Dev commands or mods.

The only standard in game solution is a Yagluth drop, or just walking really slow and being extra careful.

Originally posted by HappyShinigami:

Have been just roaming at sea for a couple of in game days hoping to run across it. Was wondering if im missing out on a easier method

Well, if you're not headed in a straight line, then you're technically adding a bit of travel time... but yeah, basically, that's it. Get in a boat, pick a direction, and go "that way" until you find them.

Bring portal mats, and expect to leave a corpse as soon as you get near them; it's not a bad idea to park outside the biome, and walk in.. after building a portal protection hut.

ty to all the replies, gonna set out and find them today

Just head east or west, should find it soon.

You won't miss these lands - a giant wall of fog is hard to miss.

It's in the outer third ring of the world roughly. The silhouettes of the biomes are well designed to the point it's easy to identify the biome from a distance. Mistlands terrain is very jagged.

I thought I was in the Mistlands for the longest time fighting all the bugs uncovered tons of the map but still wasn't finding Dvergers etc. I got in my ship and sailed the shorelines until I ran into the fog bank. Thats when you know you have found it.

Mistlands areas generate out further from the center of the world than most other biomes. Easiest way is to sail as far away from the center as you can. North and South outer most dges are dominated by Ashlands and Frozen North, but there will be Mistlands before those.