OK so still on my first run at this game, i got to a part where i have to fight some Greywolf dude, but he's kicking my ass, he kills any party member in just two hits and theres not much i can do about it. What is the best way to lvl 1 early, my party is MC, Imoen, Neera, Jaheira, Khalid and Minsc, all of them lvl 1 except Jaheira (lvl2).

I heard about some basislisk that you can kill but i can't find them and i only have one use of the Protect from petrification spell.

go to the nashkel temple and buy a scroll of stone to flesh. then head to the carnival and restore Branwen. ditch neera for branwen and get branwen to lvl3. memorize hold person spells

I understand the urge to beat a strong enemy right away, but keep in mind that one of the fun things about many RPGs is to come back to the enemy later in the game for revenge when you are more powerful. Rushing to beat powerful enemies right away removes this fun from the game, and possibly ruins many surprises while you're on your way trying to level up your characters faster than you should. There will be times you will wish that, if only you had left a certain powerful enemy alone, you could test your might against that enemy now with your current character(s) and gear.

Easier said than done, but - you can always come back later. It's not like you're required to beat the guy right now. If it's your FIRST playthrough, I STRONGLY advise against trying to level up fast instead of just taking your time and playing the game normally. You can play the game as many times as you want, but you can ever have only ONE first playthrough, ONE chance to experience things for the FIRST time.

With a little luck and strategy you might be able to win the fight now.

Your MC can cast the level 1 cleric spell Command, if successful Greywolf can't attack for a round while all your attacks hit.
Casting the level 1 mage spell Blindness (if you've found a scroll to learn it) can also work, try running away and shoot him from the distance if he gets blinded.
Also check your equipment if there are items which can help in this battle.

The battle will be easier if you return later, more experienced and better equipped. Any area can help getting XP or loot to improve your party, simply explore the maps and if something is too powerful retreat and try something else.

An often overlooked option to make battles easier is lowering the difficulty.

He can't, idk if i missed that spell's scroll. I could try coming back later i guess. But, you're suggesting me that i level up this character which is precisely what i'm struggling in?

According to the party description in his thread Help Baldur's gate noob, the main character is a Cavalier. He doesn't have any Clerics in the party.

Leave Greywolf and the mines for now - try helping Minsc on his quest first (beating enemies along the way will help you level up) - that'll also keep Minsc (and Boo) happy ;)
(avoiding spoilers so ask if you want them).

As a general tactic early on - have more characters with ranged weapons - take some shots at the enemies before they close the distance - put the best armor you've got and a large shield on your PC (or Minsc) (to improve AC (Armor Class)) and have the others attack from range while the 'tank' engages the enemy. If there are too many - run away a bit and attack again from range.
Don't forget to pause while making tactical decisions.

I found enabling several auto-pause settings to make my first game go much better, because that let me make sure party members were always doing what I wanted, without relying on a Party AI script (I never found a script that I found did as good a job as I thought I could, even when I was fairly new). Your results may vary. I like:

Auto-pause: Enemy Sighted
Auto-pause: Character Hit
Auto-pause: Target Gone
Auto-pause: Trap Detected

Enemy Sighted lets me react immediately to the start of hostilities, either by running away, freezing in place, or pulling out a ranged weapon.

Character Hit lets me review the fight and assess whether the injury sustained needs immediate attention: a healing potion/spell, ordering a character to fall back, etc. If I decide it's a minor injury, I unpause without changing anyone's orders.

Target Gone ensures that each combatant moves immediately to the next target I consider a priority, as soon as their prior target is killed.

Trap Detected is important because there is little value in detecting a trap if someone in the party triggers it before the thief can disarm it. Pausing here lets me order everyone to hold in place (if they were moving with the thief), while the thief advances to disarm the trap.

Another tip: search the fields in Nashkel. Near the west side of the map you can find a piece of Ankheg Plate. Just what your tank needs ;-)