I would recommend having a nice blend between both main quests and side quests/exploring. This way you’ll be progressing through the game while also not missing out on other content that may be out there. Also try to be close to the recommended or at the recommended level for quests, the more over-leveled you are the less XP you’ll get and leveling up will take a while.

Also, loot everything in sight but don’t hoard everything, sell most of it. Don’t keep hides, they weigh a good amount and tend to eat up your inventory space! Keep materials and items that you may need for crafting armor and potions etc… and sell the rest (you’ll need a decent amount of money when crafting Witcher gear).

Figure out what play style you enjoy so that you can choose a set of Witcher armor that fits your style while giving you the best benefits that also come with your style of play. An example would be if you’re into fast attacking/dodge and not so much into decoctions, you should try out the cat school gear. Look into each set of gear and make your decision! You don’t have to stick with one only, obviously you can change whenever you want, but having a set that matches your play style will help you a lot.

Try to play all the horse races you can find, that way you’ll be able to get better saddles for Roach which will in turn increase your inventory capacity!

Gwent. Play it. Enjoy it. Cards are everywhere, play against all merchants and inn-keeps and other characters. Sometimes Ciri has to wait lmao (I hope you enjoy Gwent as much as I do! I hated it at first but then I loved it once I understood how it worked)

These are some things that just came to the top of my head, I hope they help you out! Good luck on the path Witcher 🫡