1. most generic combo: gap-closing+the most dmg output possible in a decent amount of time: E-R-(flash)-(AA, if in range)-Q-AA-Q-(AA)-W-AA- Q-AA-R/R-Q-AA (R-Q-AA is faster but may deal less dmg if the enemy has over 25% hp when using R).E-R-AA-Q-AA-Q-W-AA-R-Q-AA in this combo you can use hydra before W or any Qs. you can skip any Q-AA in order to get in range, replacing it with Q.

you can also use: E-R-(AA)-(flash)-Q-(AA)-W-AA-Q-AA- Q-AA-R/R-Q-AA, if you want to keep the enemy closer to you (using stun earlier) in the moment after engaging (example: your jungler is coming to gank and you don't want the enemy gnar to jump away before your jungler can get in range for his cc or you want to send the enemy in base, without killing him, but he has escape up and would just run away from your combo if using the first form). it's still better to use the first form of the combo in a normal duel, since you don't waste your shield stunning the enemy.

by skipping some Q-AA from this combo, you can get: E-R-Q-W-(AA)-R-Q-(AA) (gap closing+burst)

this combo has also another form (W at the end) - video - E-R-Q-AA-Q-AA-Q-AA-W-(AA)-R-(AA) (if you use this, your enemy won't be able to flash your ultimate, because he will be stunned!)

also, you can skip any Q-AA from this combo, in order to burst the enemy faster: video E-R-Q-W-AA-hydra-R-Q

2. already-in-range combo: while camping in a brush or simply fighting in lane, you may not want to start the fight with your E, but with the stun, because you keep your E to chese the enemy after you know in which direction he will run.

R-W-(AA)-Q-AA-E-(AA)-Q-AA- Q-AA-R/R-Q-AA (R-Q-AA is faster but may deal less dmg if the enemy has over 25% hp when using R). hydra can be used before W or any Q.

R-W-AA-hydra-Q-AA-E-AA-Q - he did not finish the combo cuz irelia ran away.

you can skip any Q-AA or E for doing it faster.

i usually use this against champs like irelia, rene, pantheon (i wait them to stun me and then i start this combo).

3. highest dmg/time combo: E-R-(flash)-W-(AA)-(hydra)-R-(hydra)-Q-(AA). video

you can extend it to: (Q, to gap closer)-E-R-(flash)-W-AA-(hydra)-Q-AA- -Q-AA-R/R-Q-AA. video note: those combos ares used only for burst and not for duels where the enemy can kill you. using W right after E is not effective (you waste time of your shield). just use combo 1 for a straight duel.

a full extended one E-R-flash-W-AA-Q-AA-Q-AA-Q-R - he did not use the last auto, because he didn't need it, and he did not use R+Q because he needed knockup to stop jayce's q.

4. the flash combo: usually, even though the third combo is the best for burst, you are not fed enough in order to kill someone who has full hp with it, or simply not in range to do 3rd combo (this has a little more range). so, in order to kill a full hp adc (or a 1k hp tank for example), we use: Q-Q-E-R-(flash)-(AA)-Q-(AA)-(hydra)-W-(hydra)-(AA)-R-(AA).

this combo is the most versatile one, depending on your target's hp, you can skip auto attacks/spells or even change it's form. i will list the variations of this combo in the order of aproximate speed.

Q-Q-E-R-(flash)-Q-W-R

Q-Q-E-R-(flash)-Q-W-R-hydra

Q-Q-E-R-(flash)-Q-hydra-W-R-(AA) video (this is slower than previous one, but can deal more dmg if the target has over 25% hp before R)

Q-Q-E-R-(flash)-Q-W-R-AA video

Q-Q-E-R-(flash)-Q-AA-W-R

Q-Q-E-R-(flash)-Q-AA-W-R-hydra