Hi! Does anyone know tips to gain exp on a pet easily/quickly. Im on lost grove and my highest is lv 62 and leveling takes forever

unfortunately the only ways to speed up exp gain is to wait for an experience boost event, to use experience philters, or to have the relic (available from a previous event) which gives a small bonus.

you could try to get experience from other methods around the site, like experience orbs or by sending your pet out on missions, but that will be slower that just fighting things in the lost grove.

technically you could pay someone to level your pets for you, but if those pets exceed the level your account is at you won't be able to add them to your active party.

There area few ways to quicken the process but this will be more expensive on the long run. Here are a few added information on the items that could help.

use a philter of expedient learning to increass the exp gained in battle
This item can somtime be obtain in some festival games (haunted house/winter wonderland) or be a part of the advent calander. Otherwhise you can buy them for 100 diamond a piece or buy them from the trade broaker (in miscellanious item strangely enough) /item marketplace.

use exp orbs to give your pet added experience directly
They are a rare drop and their level correlate to the one of the defeated ennemy/wild pet, you should eventualy get some just by grinding but you can also by those on the trade broaker. Be carfull of the level requirement of the item if you buy it as a lv62 will not be able to receve a lv60 orb. This will NOT increass your attack proefiencie like grinding in the LG would, only add a certain amount of exp to your pet.