The screenshot to the right, is an example of how much damage is done while bursting. If you want to level up a lot faster than you would during "regular" training, I suggest you get GS. As shown in the screenshot, the players are doing quite a bit of damage (over 30k), and they're getting around 10,000-30,000 EXP.
Level 31-40 would be the best time to get GS, and it usually only costs about 10-25k. Some high-level guild members/friends may even be nice enough to help you for free. It would also be a good idea to create some Alts, since the Armor, Weapons, and Money are going to be even more difficult to get, if you start Bursting all the time.
If you go to the IGG website and log in, there's a button to the right that says "Draw Your Free Items", and many players have found this to be helpful while leveling up. I suggest getting the Training Voucher because it makes leveling up go a bit faster, too, but only for 6 hours or so. If you choose to get the Training Voucher, once you have recieved it after the weekly maintenance, you just double click on it, and it'll take you to Training Island. After you read the sign(s) and figure out where you should take your character, you shouldn't need near as much food as you usually would during training, since the Training Voucher automatically restores some of your health during battles (100 HP & 100 SP after each of your turns). You might not even need to bring ANY food. Like I said, it only lasts around 6 hours, and then you stop entering battles, so spawn back to Starter's Beach, Carnie, or a Recorded place.
Once you have GS, though, all you have to do is go on World, or Guild, or whichever chat that works for you, and you ask for burst mates. Some people will want you to actually buy your way into bursting, which is ridiculous, so you should wait to find people willing to let you join for free. Unless you don't care about spending all that gold on it, of course.
Below, I have directions on how to Burst, depending on your Element; Fire/Water/Earth/Wind. You must follow these directions EXACTLY.
You need a team, so have 3 players who are Fires, and 1 Water. Fire- (can be any level)
First Turn: Slowdown. Second Turn: Poison spell. Third Turn: Hot Fire Attack (GS). Fourth Turn: Hagendis Hit. (If you're a Mage, use Fire Combo Beating instead, or the strongest skill you have.) ** All Three Fires Must Have The Same Spd To Get The Most EXP ** (0 Spd is the most common)
You need a team of 3 Fires, 1 Water. (any level)
1st Turn: Shrink (GS) 2nd Turn: Magic Recovery/Water Shield 3rd Turn: Freezing Spell 4th Turn: Sleep
You have two team choices:
2 Fire, 1 Earth,1 Water (Earth will get the same EXP as Water in this team)
3 Fire, 1 Earth (only Earth gets the EXP in this team)
1st Turn: Blockage (GS) 2nd Turn: Shield Defense (use on pet) 3rd Turn: Tree Bind 4th Turn: Terrafication
Assemble these teams:
2 Fires, 1 Water, 1 Wind
3 Fires, 1 Wind
1st Turn: Speedup (use on pet) 2nd Turn: Shield Smash 3rd Turn: Cord 4th Turn: Coma
This part is a bit hard, so bear with me. One of the basics of bursting is to have Cows, Sheeps, or Horses. These three pets can be found near or around the farm on South Island and can give you more EXP.
This is how you control the Cows, Sheeps, or Horses.
1st Turn: Defense 2nd Turn: Defense 3rd Turn: Defense 4th Turn: Attack (Don't use their skills because that might mess things up, causing the beetle to die in one hit.)
If you're a Fire Mage or Warrior, you won't need any speed.
If there are three Fires: Fire warriors don't need speed. They just need high damage so if their SPD is lower than any of the pets, then they will absolutely combo. The success rate is very high. Sometimes the pets will mess things up if they all have different SPD, but there is a low chance of that. If all Fires have 0 SPD, then they will combo for sure, no matter what.
You may also want a Shadow Pestle, even though it's for level 50+. To make it (by compounding), you need a Steel Bracer, Bronze Boots, a Ghost Halberd, and (optional, it gives a better chance of success) an Alchemy Book 2. The Shadow Pestle looks like a ball on a stick, and it has ATK +55 and SPD -99. A Steel Ball 80T or Steel Hammer 99T would also be helpful, though they give -80 SPD (80T) or -99 SPD (99T). The Steel Hammer 99T comes from the Item Mall.