From watching some of Taj's videos I can see that he makes a wondrous use of the teleport. Basically what I'm wondering is, are there any specific circumstances or situations where using the teleport would be recommended? Possibly to be used as a retreat or a follow up? I've never really attempted to incorporate it into my game, so I'm somewhat in the dark.
I'm not Taj, but I think I can give you an idea. First though, you must understand that its up to you when to use the teleport. As for my Mewtwo, I use it as an on the edge trick (Not Taj's... I never bothered to try to learn it like that... I didn't want to be accused of being a copycat lol), to take the opponent's back, to dodge down to the stage to avoid an air move, and for mind games. Using it to tech-chase your opponent is a good idea, so long as you don't become predictable with it... mix it up with dashing and wavedashing. Not having a name tag when playing M2 is also advisable, as it makes it impossible for the other player to see where you're going when you Teleport. When Taj posts here, I'm sure he'll have more tips for you...
Edit. Having just watched the matches that you recently put on youtube, I'd have to say that you should probably encorperate Teleporting. You've got a pretty good M2, but there were times that Teleport would've helped a lot...