Canned definitely helps; well socialized people all use it. Some consciously, others not, but they all do it. So join the conscious group
That being said... as much as I hate to sound patronizing (my sincerest apologies, I hope you don't take this the wrong way), this will be a long and difficult journey. A very clever person (can't remember who, maybe a quote junkie will help me give credit) once said that confidence comes from comfort, and comfort comes from repetition. If you freeze up around beautiful women - man, I honestly feel your pain, but trust me - talk to enough women and there will come a time when you'll notice it ain't all that difficult. Put yourself into these situations as often as you can and don't let the initial failures discourage you. Believe me, with persistence, the nervousness will go away and you'll start feeling more and more comfortable approaching and talking to women. Just keep at it and invest time. As my mentor says 'unless you have worked a thousand sets, you do not know shit'.
And seriously, don't worry about the whole 'alpha-not alpha' thing. First, it sounds really really gay, second - how can you expect decent results when the back of your head is constantly going 'oh boy, was I alpha enough just now?'.
I'm gonna take a leap of faith here, and do correct me if I'm wrong - when you're around a girl, do you have this voice in the back of your head telling you that you should be doing something? That voice that says 'I should approach her, open and demonstrate value'? My advice is - ignore that voice. I had it and most of the guys I've taught say the same thing 'a PUA should do this, a PUA should do that...' Seriously, that voice is one hell of a whiny bitch. It makes pickup feel like work, when it should be fun. Take a chill pill and enjoy the process

Everyone I know who got somewhere in pickup has fun while doing it. All the others become quitters.