You should decide your job during the tutorial at the beginning of the game, which is based on the skills you will invest in.
If you dont know whether a skill is good or not, save your game before investing a point in it. Then put a point in it, and try it out. If you dont like it, just close the game.
When you are asked to bring some Pure water, bring 3 empty bottle for Inferno quest.
If you upgrade unsuccessfully a weapon or armor, DO NOT try to upgrade the weapon/armor again. There is a high probability that it will break and turn into a very lame weapon/armor. If you have Cubic for strenghten aid, it is possible though to upgrade it. The best method to strengthen an item (would be great if someone else could confirm this) would be to strengthen it 2 or 3 times, and when it starts saying that 2 stones are needed to continue strengthening; stop at that point. If you continue, chances are that it will fail, if not be destroyed.
Items CAN be destroyed on the second Strengthen. (Probably can be destroyed on the first strengthen as well)
You'll likely get weapon/armor upgrading is unsuccessful when it reaches level 4 (without cubic)
Equip a soul to the weapon/armor after you're done upgrading it so you won't lose the soul with the item if it fails.
Do not sell the Rock cutting sword even though it's lame. You'll need that to complete "Relic king statue" quest.
Slow the game speed if you feel it hard to fight bosses. Fasten the game speed if you want to grind. A slower game speed will be helpful when you fight the Guardian and bosses after.
The best places to grind are where several monsters gather (usually of one type) in a group and have low Hp (ex : mutons). The best thing to do is to lure them all to the same location and then kill them all. Remember, monsters with high Hp doesnt mean they have higher exp. at all.
Sell your loots. Don't trade it for "hunter points". If you want to get hunter points, just do the quest given by the leaders of the village. That way, you'll earn more money.
To get random cubic, you shoud have an internet connection. If you could tap the right place near the "X" button at the menu option. You could get 5 cubic maximum,so dont try to find it again after you got 5.RANDOMLY tap the area near "Randomly Get" between the ad space and the X repeatedly and you will get it.
Use SCAR or VENOM KISS to bosses. It will be very useful,when you are avoiding boss and recover your Hp,the boss will have theirs decreased in period of time.
SAVE if you're near your limit (when you're surrounded by many monsters) so,if you were die in the end,you can back to main menu and load. Immediate revival will do nothing good (costs 20 % exp and money or 5 cubics if you have). Because you are 'invisible when you got back to the game,you could used potions and heal to get back in action. FYI,immediate revival in fightning bosses means you'll have to go back to the room before the boss'.
Tip for Shooters. You know that if you hit C, you will lock on to an enemy and vastly improve your accuracy. Shooting at the enemy will consume stamina, but you can move to higher ground to avoid being hit. HOWEVER, if you jump and tap down you will hit the enemy (as long as the target lock remains) WITHOUT using stamina AND you will hit them even if your shots appear to be going over your target's head. Very useful for many bosses where jumping constantly keeps you from being hit.
Constantly running out of inventory and don't feel like selling those items because you think you might need them someday? Well then you can make up to 3 save games 2 of which can be mules adding 140 additional inventory spaces, they all 3 share the same market account so transferring between them is a cinch.
If you feel like you've mastered just about every enemy and can take them down without breaking a sweat, something to consider is finding a high level accessory one without an element perhaps with a drop or collect built into it with 3 additional slots and beef it up however you see fit, you won't do as much damage as you would if you had the right element but if you're farming for loot you won't have to have 3 accessories built up and will save time as well.