I'll just list this in bullet points (some of these might actually have been stated earlier by other pedians)
1.) Insect glaive uses 4 extracts;
red, orange, white, and green
singulars
red - attack (front)
orange - defense (lower sides and lower front)
white - jump (limbs and wings)
green - heal (usually found in tails)
combinations
white + red - attack up + usual red and white extract results
white + orange - def up + earplugs + usual orange and white extract results
white + red + orange - attack up and defense up large, earplugs, and all extract results
2.) Set mostly used for IG(based on online g rank encounters)(not counting star knight ofc)
u-ka-u-ka-u
sharpness +1
mind's eye
weakness exploit
w/ 11 slots
3.)Combos
after getting both red and white(this doesn't however apply to the speed run demo version of the game)
Spam mount or spam x-x-a
The usual extract combination routine is
red - white - mount monster - orange - red - white - mount - orange - etc.
4.) Some tips
a.) You can mark the monster by holding R and then releasing it when the triforce is targetting the monster (I forgot about this, IG is banned for more than 2 months now). You can also mark him in the middle of a combo (just press R.) Insect glaive is like a buffed version of longsword (they seriously nerfed this one ;-
.
b.) Mounting master/Rodeo God is a very good skill for insect Glaive (good thing you'll get one mounting +10 latter in the game).
c.) Mind's eye is also a very excellent skill for ig users, especially against those with rock skin.
d.) Insect glaive's kinsect attack can be charged.
e.) Get extract up to elongate extract effects
5.) Best IGs (for me, yes I forgot their names)
a.) Daora IG - Ice
mostly used against Teo
b.) Crimson IG - Fire
mostly used against chameleos
c.) Chameleos IG - Poison
mostly used against daora
6.) Why use IG?
A would be good contender for IG was the longsword, both of them have good reach, fast combos (IG is faster tbh). But the LS got nerfed to oblivion (can't blame them, inb4 LS was unstoppable). Anyways, both of them also has decent attack and great buffs specially IG which offers the player an attack up l.
Mounting is also highly appreciated in a team because it makes the hunts 2 times easier. Unlike other weapons IGs don't need ledges and other... forces to help them mount.
7.) Personal opinion (the whole comment is my personal review :v)
After a hundred uses of IG in the real game(excluding demo), it needs to be nerfed ;-; (seriously though, it's too op of a weapon). Anyways, use it at your own leisure. Next dlc is really close and it is star knight
8.) Ultimate kinsect (I'm kinda lazy to take a picture of it so... goodluck I guess?) (Jk, there are some guides about it online)