In order to create an effective Experience Chain (5+), there are certain things to keep in mind. I will be making references to NA and JP parties, but I'm not saying which one is better. I've been in equally good parties in both, but the play style of each is generally very different.
Puller(s)
Having a good puller is very important. And having multiple pullers help dramatically.
In a lot of NA parties (except a few), there is usually a designated 'puller' or 'fishermen'. If an area is not crowded or monsters are close to the camp, this can work very well. However, in open areas or crowded areas (say Kazham), it is always a good idea to have 2-3 pullers. All melees should have some kind of ranged weapons equipped.
In JP parties, there are no designated 'puller'. All melees (except PLD) will go searching after each battle.
Communication between Pullers
If you have (and you should) multiple pullers, you should not pull unless you get an 'OK' from other pullers. Each puller should have 2 Pulling Macros:
1) /p <t> Sighted, Ready? <scall8>
2) /p Pulling <t>. Ready for battle! <scall9>
/ra <t>
Macro 1 is to confirm the pull, Macro 2 is the actual pulling.
Checking monster
Before pulling a monster, you should always check it. You will never want to pull an IT++ to start a chain! Nor you will want to end a Chain #5 with an Even Match.
Generally, you will like to do something like the following:
1) Tough or Very Tough to start the chain and build TP
2) Incredibly tough, skillchain and magic burst
3) Very Tough to build TP
4) Very Tough to build TP
5) Incredibly Tough to finish Chain. Release all TP and magic burst to kill as fast as possible for Chain #5.
The above can varie based on the setup on your party. It's just a general idea on how Chain #5 should be obtained. If you have 3 RNGs or 3 BLM in your PT, just forget the above and pull all IT. But that doesn't happen very often.
Timing
Here's a chart on the time limit on sustaining a chain.
[High LVL in PT] [Time for Chain #1] [Penalty after each chain]
1-9 ------------ 50 sec ------------ 10 sec
10-19 --------- 100 sec --------- 20 sec
20-29 --------- 150 sec --------- 30 sec
30-39 --------- 200 sec --------- 40 sec
40-49 --------- 250 sec --------- 50 sec
50-59 --------- 300 sec --------- 60 sec
60+ ----------- 350 sec --------- 70 sec
For example, if your PT's highest level is 55, after 1st chain you have 3 minutes until the next chain! Just let your mages rest for 1 minute (usually back to full), then pull the 2nd monster.
After 2nd kill, you will have 300-(penalty*chain#), which is 300-(60sec*1) = 240sec until next kill. So you can rest for about 40 seconds or so. Mages and Paladins need MP to sustain the chain. And if the time allows, let everyone heal up.
Before ending Chain #4, a puller should already be searching for the next monster and ready to pull as soon as the monster is killed. This is the only way you can kill fast enough for a Chain 5.
Chain 5 on Incredibly Tough before level 40 is extremely hard, becuase you need to kill the monster in less than 1 minute. So either finish Chain #4 using an Incredibly Tough or finish Chain #5 with something easy.
Choosing an area
You should always perform a search in various leveling areasbefore heading out. You never want too much competition or else it will be pointless to fight 1 monster every 10 minutes. Generally, 2-3 PTs is ideal for large areas such at Terrigan, and 1-2 PTs for smaller areas.
If you didn't search and you find out there is already a party at a 'good' camp spot. It is very rude to just camp in front of them.
Don't be afraid to try out new locations. You don't have to go to Kazham at level 25! Being level 33 doesn't mean you have to go to Garlaige! There are lists on various websites on suggested leveling areas. Print out a list.
I've been in Japanese parties that tried out a new area (which worked great) because all the popular spots were taken. How did you think people come up with lists of suggested area? Someone had to try them out first right?
Monster Pop/Aggro
There will be times that you are forced to camp at a location where monsters will pop or in the path of an agressive monster. The respawn timer on regular monster is 16 minutes, starting from the time of death. Someone in the party should be keeping track of this and notify members when the time is near. Then pullers should stay at the camp and wait for the monster to pop.