You should grind above your level, or at least grind on yetis. The mobs you're fighting right now are green to you, as soon as a mob turns green, you get significantly less xp.
For instance, you're fighting a mob that's lv 57, to you, it's white, let's say you get 3000 xp per kill.
Now fight a lv 56, you will only get 2400 xp per kill. (made up numbers)
If you were fighting a lv 58, you would get only 3200 per kill, so as you see, the xp lost for fighting green mobs is significant.
However, it works the other way around too, if you're fighting a lv 60 mob, you'll get 3600 xp per kill, but if you fight a lv 61 mob, which is orange to you, you'll get 4200 xp per kill.
Secret to grinding on fast killers: Grind on orange mobs.
It's also best to find a good attack pattern that you can follow which is perfect on certain mobs, what this means is:
If you can kill a lv 61 in longshot + power shot (sorry, I never got to a high level on a euro char, so I don't know any higher level attack names), that's good.
BUT! If you're able to kill lv 63 mobs in longshot+power shot as well, might as well grind on them right? It's the same thing as fighting the lv 61's, but this way you're getting ~400xp per kill more.
Also, another grinding tip is to not fight party mobs, and unless you're able to do it, don't fight giants. Usually giants can kill euros if they're soloing. I've heard a good tactic for fighting giants is to take off your "suicide" buff (crossbow extreme). If this really is a good idea, then here's a small trick to help maximize damage.
On these lv 63 mobs (we're still in the same example here), you're able to kill one with longshot and powershot before they even reach you, so the trick to fighting a giant mob is tos tart longshot, hit zerk, then do powershot, and THEN take off crossbow extreme, this way, you just got significantly more damage out of 2 attacks than you would have if you took off crossbow extreme right away. It's also good to have good reflexes however, like powershot can knockback enemies, so if you successfully knock back the giant, then you can afford to get another hit in there before taking off crossbow extreme.
I also know crossbows are able to knockdown the enemy, so try knocking down the giant before he gets to you, then you can use crossbow extreme.
On that note, another tactic that might work is after the giant reaches you, then try to knock him down as much as possible (as well as knockback, but knockdown especially), and as soon as you get him knocked down, throw up crossbow extreme and do a move that can hit the mob while he's knocked down, after this move is finished, take off crossbow extreme again and continue to fight.
The best part about this tactic is if you're lucky enough to score a crit with crossbow extreme on, you just knocked off like 12 seconds of giant battle time
Good luck dude, hopefully what I said made sence.
) medium, or slow. So, after this long, kinda pointless paragraph, how long does it take a person to get 1% to their next lvl??