Step one is to make sure you've got the basics covered. That means making sure that you have a good resume, and that you go through the classifieds, local job boards, and other listings with a fine tooth comb. Pay attention to which boards post HVAC openings, and which ones stick to professional types of jobs. That'll keep you from wasting time and effort on boards that won't help you. Consider posting your resume to employment websites for potential employers to find. Be sure that it calls attention to all your best features and is well written without any errors.
Your resume is your first impression, after all. No one wants to read one that's badly spelled, poorly organized, or takes up too much space. If you don't know how to write a resume correctly, take the time to talk to someone who does. They can help you put together something that potential employers will find attractive and that will make them want to hire you. At a minimum, take the time to look for resume tips online or at your local library. How you present yourself can have a lot to do with whether or not you get the job. Everyone needs to make a good first impression with their employer.
Next, start using industry specific search methods. That means finding out which companies take on HVAC employees in your area. Get in touch with them to find out if they have any vacancies that might not have been posted. You'll be surprised how much of a difference this can make in your job search. Don't forget to network in the industry, either. If you know a few people, you might be able to find out about openings that will never be publicly posted. It really is all about who you know, but it's not hard to find someone who can help you. Be sure to leave your name and contact information with any company you call. That way, if something does turn up, you'll be contacted about the job. Its okay to follow up from time to time, too, but don't do it often enough to become annoying.
Be sure you check out non-private employment options, too. Government and county installations need HVAC professionals just as much as private companies, and these positions tend to come with good benefits and reasonable pay. You can often find these job opportunities just by checking out the county and local government websites. You can often even submit your application through the Internet, without having to send in a paper resume. This can be very convenient for people who don't have the time to stop by in person. Just make sure you're as professional online as you would be in person.
Contractors need HVAC techs, too. Take the time to get in touch with some of the general contractors in your area and find out if they're in need of someone or if they know someone who is. Construction companies and contractors often employ a few HVAC technicians of their own to manage subcontractors. Don't forget about working for yourself, too. You can subcontract, or start your own business with little more than a good toolset, a reliable vehicle, and some decent business sense. Many great companies have been started by people who aren't satisfied with their job opportunities elsewhere.