errmm your not really doing much wrong but you could do alot to improve your game...
most of these would come from Rusty's guide... so yeah to save me time Ill post a link to it...
http://smashboards.com/showthread.php?t=162635
If you use the techniques in that guide youll have a decent snake...
Some of these techniques are Mortor sliding, Shield counter and shield dropping nades and cooking is also very important.
You used short hop Dair once which is good but its one of snakes best KO moves along with Up tilt which kill at very early percentages such as 90% or 100%.
Full hop Nair is also a very good move and can be used for edge gaurding and hiting opponents that SH too much.
But yeah I could say alot more but if you read the guide that rusty made youll learn a hell of a lot more...
