Some suggestions:
Do not drown the rice paper, just dunk it in the water and pull it out, shake lightly, place on plate or clean flat surface. By the time you finish organizing the filling it will be pliable enough to fold, but not soggy to avoid breaking.

Use the larger size rice paper. You can fold it taught like a sushi roll, to make it look cleaner. Sometimes for presenation, I used to cut off the ends before serving to make it look cleaner..

Use some Chives (asian variety)- cleaned and dried off. cut the root bulb end off.

cut the Prawns in half, lengthwise to 1. devien it. 2. to make it fold into the spring roll easier. (I cook the prawns after quickly marinating in sugar and salt) boil them quickly.. boiled whole, but deviened, then peeled, then cut in half.

Layout is important.
lay out the prawns first then the lettuce (use red leaf lettuce is nice) Place the rice noodles. Remember rolling the spring roll with things arranged, makes the translucent rice paper (spring roll) look really nice.

If you roll it up.. such that the sides (right and left) overlap as you roll it up.

Traditionally, boiled pork is sliced thin and used as a filling, Acutally pork belly, but that is very traditional. Fatty too much.

Vietnamese (asian) mint is essential. Carrots are nice.

Dipping sauce.
variations include
1. peanut sauce. such as hoison sauce mixed with peanut butter and heated in microwave.. 3:1 ration of hoison to PB.

a hint of chilli pepper sauce is always nice to add to sauce before eating for those who like a little kick.

2. nuoc cham - fish sauce, lime, sugar, garlic, chillis

look at this: http://www.youtube.com/watch?v=uw-7pYq7wSc

Good Luck!