I try to get everyone to try playing on Death March, no fast travel.

I did my first playthrough like this. There's so much to see in the world and so many paths to take. Fast travel is neat and all but you may miss out on so much. I took it a step further and also didn't leave regions/nations until I completed the map. I found more incidental quests by taking a wrong turn or a shortcut over a hill than I did by following the main quests.

On Death March: It's actually not hard at all and feels like how the gake should be played. What it actually does is forces you to look at the bestiary, learn or guess weaknesses and attack patterns then use potions, spells and pils to fight enemies. It actually feels like playing the witcher as lore accurately as possible. Going to the local herbalist, buying supplies, meditating then hunting down the enemies.

Ignore the advice you saw in this thread, except for the one about trying the DLCs, and enjoy the game however you wanna play it. Romance both options if you want, be a terrible dad if you're so inclined, etc. Have fun, it's your first playthrough so enjoy it unspoiled ane cherish it, you will love it and go for a 2nd, 3rd, 4th, 5th and maybe even more runs and you can minmax things later on in these runs.

The only thing I'd say you shouldn't do is skip the dialogue and cutscenes, and sidequests. This game has a very well-crafted story (which is the main attraction) and that goes also for the sidequests so enjoy them fully.

Quen and side step a lot during combat. Focus on getting sets of armor and weapons because they are better than whatever weird ass stuff you throw together from loot. So that means you’ll have to visit armorers a lot. Do not ignore Gwent. It can be fun. Pick one girl and do not romance them both. Make sure you make Ciri as happy as possible. A lot of quests are about choosing the lesser evil. So basically you’re setup to make a bad choice no matter what. Which makes it interesting honestly. This game is really interesting and rich in story. Explore everything. Have fun.

Pace yourself.

This is a huge game, i thought i was right before the end game twice but it just keeps on going. I have yet to start on the DLC’s and i was actually hoping to have moved the other sp rpgs on my todo list by now.

Its great though, if only cyberpunk was this big but they purposely kept it short because 70% of witcher 3 players didn’t get to the halfway point

Don't romance them both.

Pick lots of ballise fruit in White Orchard. It is tougher to find later on.

Kill all the cows in White Orchard. Repeatedly. Farm them. Good early game coin selling their hides.

There's a mod that makes picking up loot less of a pain in the ass. Game is unplayable without it imho.

Don't let the upgrade, potion, etc system overwhelm you. My brother gave up cause it seemed too complicated for him. If you mostly ignore it and just play for a bit, it comes naturally

Always buy new shoes in the afternoon - after your feet have expanded.

…Oh, you mean about the game?

No advice really, just wanted to say I absolutely love the game and have played through probably 6-7 times now. Very addicting and is especially comforting to play in the winter, with all the beautiful scenery and sounds.

Keep Quen up, roll about, hit stuff.

There's a couple of enemies where this doesn't work, but it should get you through the trickier combat sections.

Don't forget the DLC, and for all the praise Blood and Wine got because of it's size, don't sleep on Hearts of Stone - it's the most memorable part of the game for me.

Oils

Witcher 3 can be played like the puzzle game on max difficulty.

You don't have to grind level or have good controller skill to beat those boss in max difficulty. In fact, it like puzzle game. If you know how to beat the boss (read in game wiki), or have oil, spell, or do something before, ... you can beat a boss easily, without need much skill or overlevel.

beware the botchling (don't progress to far to fast, level up or things like the botchling will be frustrating)

The story was difficult to follow, for me, and plays a significant role in the game and is likely to influence your decisions. What I wish I did and what I recommend you, is make sure you pay close attention to it in the beginning, knowing who's who, who's battling who and why. Consider taking notes haha

Edit: the story and the game are fantastic, I hope you enjoy it like I did. I recently finished the game and started with the extensions.

Pay attention. The game wouldn't always lead you to what you need to do. Some times you'll have to figure things out. There isn't just a marker on the map for what you need to do next. That messed me up because half the time I was following a marker but then there would be a line about giving someone an item or something in my inventory I missed. Ignore 100%ing every quest. Learn to parry and roll. Also, explore! I've run into very cool side quests! It feels really cool to just stumble into a story before a character even sends you out on the quest.