From my experiences coming to the US where they played these strange games called Football and Baseball I would suggest you do all or some of the following:
1. Find friends or co-workers who play or have played the game. Go to games in the US with them. Ask them questions about the play and about the refrees decisions. The friend should be one who wants you to understand the game.
2. Just like baseball has little league, school leagues, college and the pro. leagues there are many soccer leagues of all levels many of the free to watch.
3. On ESPN3 you can watch various Soccer Leagues that have already been played. The running commentries give you a very good picture of the action and help you understand the rules.
4. Search on google for the basic or simple rules of soccer ( football ) wading through complex rules in books ment for refrees will put you to sleep and are not needed to enjoy the game.
5. It would be best to not wear any team jerseys at a professional game unless you go with a group who know what they are doing.
6. Finally soccer is a very low scoring game and if you cannot appreciate the tactics and techniques being used by the two sides you may find yourself bored by many games.
7. For me personally I only enjoy watching sports I have played in my youth ( mostly badly )
So I do not enjoy watching baseball or football, not even the World series or Superbowl
