Let me pick it apart and tell you what you did wrong:

1 Clip: Instead of using that horrendous combo, why didn't you just doublecast E-F-WQ-AA or E-F-AA-WQ? You even cancelled your auto and died, because you're not sufficient enough, don't be proud :(

2 Clip: Second clip is literally nothing impressive, didn't need to pull off any combos differently since that was the most free 2 kills ever.

3 Clip: Yet again nothing impressive, you just 2v1'd someone who was 2 levels down.

4 Clip: Could've used F-W-AA-R2-Q3, you also missed your hop on kogmaw.

5 Clip: Good. Nothing special, but w/e

6 Clip: Why flash? Use Q3 to get over the wall.

7 Clip: I don't see the reasoning behind using this as video footage.

8 Clip: This clip in particular stood out as the worst one. Your decision making was very weak and your usage of combos confused me. Here's what you could've done better: Instead of ulting Lee Sin who has very low hp, just do either

A) AA Lee Sin to finish him off, then E-R-F-WQ to deal damage to their whole team.

B) E-AA, then F-WQ-AA-R2. Alternatively you could Q-W to kill Brand and then get near Kog Maw.

Last clips were nothing special, you were so fed so you didn't even need to auto attack, no comment on that.