Okay, well firstly there's a lot you can do to improve your seduction skills and fundamentals without actually approaching. It's important to strike up conversations with eceryone you meet, and try to get them sharing (register chicks, etc... anyone who has to interact with you for whatever reason... also friends of friends, colleagues, family friends, etc). Also, to join a gym, buy new tighter clothes, buy cologne and jewellery and boots if you possibly can, also to practice your posture and walk, not leaning in to conversations, and not doing stuff like supplicating or qualifying yourself in your everyday conversations, leading...
Now about approaching, AA is all in your head, I am sure you have, in the past, struck up an idle conversation with a bystander or say, someone who was queueing up with you for something, etc. Likely you used a situational opener. The sky didn't fall in, etc. "Approaching" is basically just the same thing, except on steroids. But in the past you probably (1) didn't do that if she was cute, cos you were nervous, (2) didn't use a direct or "genuine interest" opener. Your goal is to get comfortable with these aspects through repetition.
Some other points -- what we experience as AA is actually the rush of adrenaline which nature provides to help us to be our best when we spot a mating opportunity, same as if we're trapped by fire we get a rush of adrenaline and discover superhuman strength to smash our way out of a burning building, etc. So in that sense there's really no such thing as AA, it's a matter of routing that adrenaline where it's meant to go -- into a flirtatious conversation with a cute girl.
Lastly there is the matter of goal setting, grit, determination and forcing yourself to push boundaries by doing things that are currently outside your comfort zone. Set yourself small, achievable goals: I will smile at 5 women in the shopping centre today. Or: I will say hello to at least one girl I find attractive. (Implicit in these goals is you are not allowed to go home until you have met the goal).
The newbie assignment is the perfect way to do this: It's designed to give you small achievable goals and to get you comfortable with each step (such as just smiling or making eye contact with a stranger) before proceeding. To keep yourself accountable it's good to start a journal to track your progress through the 10 days or so of the assignment (they do not have to be taken consecutively, 1-2 days per week is fine, and the activities can be slotted into your usual routine).
A note on rejection: you must overcome your fear of rejection to have any hope of ever becoming a seducer. If you get your validation and sense of self-worth from outside aproval you'll crumple when you get your first harsh blowout. Remember, you are the man, you may be far from perfect but you are on a trajectory of self improvement, you are approaching to meet a personal goal and to gain reference points, not to get your target's approval, that's nice when it happens but is only the icing on the cake. Think of yourself as a scientist who every day prepares 20 test tubes and puts them in an incubator, only once in a while does anything interesting happen that's worthy of further investigation, but he doesn't get all butthurt over every dud batch. They're all just part of his journey to results.
Some personal experience: First girl I cold approached with a compliment -- outside my uni -- my heart was pounding with adrenaline -- she took one look at me and ran away. Haha. But, I was exhilarated as I had overcome a personal fear. Next approach went much better. I think probably the same week I met Leticia on a tram who ended up being my gf for 6mth (we are still friends, she called me last night to catch up and make a coffee date for later in the week). If you go out approaching this week you could get surprising results!
What I used to do when starting out was get my good clothes on, cologne and jewellery etc, and hit the shopping centre on a Saturday morning with the goal of doing 10 approaches before I could go home, and man, I still remember the crippling approach anxiety, walking around the centre for 45 min+ at a time, seeing cute girl after cute girl and being stuck in my head and pussying out every time. Franco also reports same thing IIRC. So what you do in that case is try for some warmup -- award yourself a break for coffee and strike up a conversation with someone (anyone) in the shop. Or, do some shopping you need to do, and chat with shop assistants (these don't count towards your goal).
And, above all, just steel yourself against rejection, take a deep breath and do it. Even experienced seducers get AA!!
Hope it helps man.
Ray