The first step to becoming an official is to approach your local officiating governing body, i.e. Canada C.H.A. U.S.A. - USA Hockey, or your local league office. This will put you in contact with other officials to set you on your way.
The next step is to get out there and "just do it" experience is the key to your success. Any game experience is invaluable, regardless of the level of hockey played. Progression to better games comes in time. ANY game is a good game to officiate. You will inevitably draw from all your experiences and grow as a well rounded official.
Training is available to you by way of official training schools and camps as well as power skating sessions in both Canada and The U.S.A. These are key factors in your development as they will give you the technical skill set needed. Many of the people who instruct, are current or former officials in the N.H.L., who have been students at these very same training camps and schools.
Some of the topics that are emphasized include, on ice positioning, signals, penalty calling, skating skills, and off ice theory sessions to give you a sense of "the game"
Present at these official's schools are representatives of leagues such as the N.H.L., A.H.L., E.C.H.L., C.H.L., U.H.L., Canadian Major Junior Hockey League, and U.S.A. Hockey associations. These representatives are there to help develop and encourage young officials to further their careers in officiating.
Make no mistake about it, fitness is a key factor in your success as an official, Fitness is measured and monitored closely by the league to ensure the staff are ready and able to do "the job", game in and game out.
Remember, whether you are a first time official, have some experience, or are looking to officiate after or during a playing career ( at any level ). The key to your success is you. You need to get out there and "just do it"