Deck building is one of the many skills of Netrunner. It is one you can avoid totally by net decking (finding a deck on one of the online sites, such as NetrunnerDB or Meteor and playing that), but I think it is one of the most exciting parts of the game and one that helps you develop as a player.
So, what do you really need to do to be a good deck builder? I’ll be honest with you, to create something truly new that is also competitive you are going to have to put in a lot of time, practice and, unavoidably, be a little bit imaginative. To do this, it’s really important that you have a good understanding of the current meta-game. Creating a new competitive deck (if that is your goal – remember it isn’t everyone’s) is going to take hundreds of games and much iteration.