- Ignore the procedural quests entirely. They're the ones marked with this icon:
. Pretend they don't exist.
- Don't feel like you should be completing all the question marks on the map. If you come across one and you have the time to spare to do the objectives there, you may as well, but otherwise you don't need to get involved.
- Look for the tomb locations online and go there when you can. Tombs are fast, relatively simple, and award an ability point. Early on, each new ability point makes a huge difference as it gives you a new gameplay mechanic to use or a significant upgrade to a previous one.
- As others have said, don't just try to go through the quests in order. However,
do go as far as the point where you deal with a Spartan general. This will give you your first legendary item. You'll eventually want lots more of these, but when you get it, it'll probably be your best piece of kit, and stay that way for a while.
- Eventually you will want mercenaries to attack to grab their gear (and maybe recruit them as crew for their ship). However, early on, they can be a pain, because they're much stronger opponents than standard enemies. You might therefore want to just pay off bounties (or kill the bounty contractor, who'll be marked on your map), until you're okay with the mercenaries. Once you are okay with the mercenaries, go after them whenever you see them. The bonuses for increasing your standing on the mercenary tiers are pretty good and some mercenaries have legendary items, including one of the best bows in the game (Hades Bow - get it when you can)
- Every time you go near a quest board, check it, and accept anything that's marked as a contract. They'll be things like kill a certain number of archers, or ships, or bandits, or wolves or whatever. You'll complete those naturally as you play the game and you'll get awarded gold and XP for having completed the contract.
- Weapons and equipment can be upgraded to match your level. However, the game should be giving you weapons close to your level anyway, so unless you really, really like a piece of equipment, you probably don't need to upgrade. Later on you will want to, especially as you start getting good sets of stuff, but that's for later. Other people are suggesting turning down the scaling, bear in mind if you do that, it will result in you getting gear four levels lower than you.
- Rethink your abilities regularly. You can reset your entire skill tree for a low cost in gold and reallocate all your ability points. This will allow you to try new skills or demote skills that are less useful than you thought. How useful you think each skill is will change as you play the game. The skill that is unarguably among the best skills no matter how you play the game is the healing skill.
- Your inventory menu allows you to unlock build slots that let you save predefined equipment sets and quickly swap between them. You should think about having, at the very least, a build for fighting multiple opponents head-on and a build for stealth (whether that's assassin-oriented or hunter-oriented). Unlocking all the build slots is expensive but even having two will be a good time-saver.
- Your adrenaline bar isn't meant to be saved for when you need it. Use abilities often.
- Probably this is something you don't really need to worry about now, but the way weapon scaling works is: weapons get better every level, but they get new perk levels every 10 levels, with that increasing happening every level ending with 1 (so, level 1, level 11, level 21, etc). Upgrading a weapon from, say, level 20 to level 21 is a much bigger deal than upgrading from level 19 to level 20. It can be worth keeping that in mind when deciding when to buy upgrades.