From my differing experiences:-
Your first wedding is a gut churning experience of nerves and worry. Once your over that hump you can see where you stand and if you are happy with your pics. If you are very happy with the pics you are either David bailey or arent striving to imrpove and it may not be the job for you.
From advice on here i gathered before my first wedding, I scoped the venue out beforehand, met the couple, got used to my gear, checked the weather, brought lots of spare umbrellas, bought lots of spare batteries, mem cards etc.
Afterwards i thought i done 'ok'. Put some pics up here and i realised they were, well, not very high quality (i was going to say **** but some were nice lol).
Back to the drawing board. I have now started structuring my day. Im not there just to snap away, its esentially a long drawn out photo shoot over multiple locations.
I start planning shots to get in the brides house, then the church, pics of the groom etc, service, then after it we have confetti shots, crowd shots, bridal party then im starting to get more top heavy with the couple portraits. Ive shamelessly stolen lots of poses and ideas of this website and the welath of brilliant togs that post here. I have lots of poses printed on sheets to try and work through with the couple as a starting point. You will then get some 'of the cuff' poses and ideas about the location and gauging the mood of the couple. your then onto the reception to get detail shots, cake etc and speeches and first dance. Now im starting to realise the limits of my gear and my wife is going to kill me if I order a full frame camera and 70-200mm F2.8 with VR
The scouts got it right "Be prepared"