In my last 15+ years as a career coach, I've worked with many professionals who feel "rusted out" in their current career. They want to make a shift. They talk dreamily about how much greater their personal and professional lives will be if they can just go where the grass is greener a/k/a a different industry or profession.
Sadly, most never make it to these greener pastures.
Changing careers is like driving down the highway at 200 miles per hour and wanting to get off at the next exit. You need to slow down, signal, and move yourself towards the ramp with plenty of time or you'll miss it. Failing to do the proper steps could also lead to you crashing. You might even hurt others in the process. In short, changing careers is A) not something to take lightly. And B) takes planning and patience.
Caution: Don't jump out of the frying pan and into the fire.
Choosing a new career path should be done with care. Spending time with people who do the work you want to do is vital, along with extensive research. I've seen many people hastily leave one career, only to end up in a worse one. You've got to be sure this is right next career move for you so you can fully commit to the process. Otherwise, you could set your career back.
Once you've identified a new direction, here's the single most important thing you should keep in mind...
Employers don't see you the way you see yourself.
Just because you have realized you want to go from being a business analyst to a marketing manager doesn't mean hiring managers will too. The No.1 roadblock to changing careers is the ability to market yourself successfully without a track record of success in the career you want to pursue. Employers like to hire proven professionals. For them, it's always safer to hire someone with existing industry experience. In order for you to convince them you can do the job, you have to connect the dots for employers. This begins with a full assessment of your transferable skills, followed by the proper branding of your career tools. Your resume, LinkedIn profile and cover letter will all need to tell a clear and compelling story of how your past work experience has prepared you for this new career path.
A business analyst has project management, data analysis, and researching skills that would be highly relevant to the marketing manager role as well. Showcasing the right skill sets will make it easier for the employer to see how you could successfully make the transition.
P.S. - Let your passion show!
While the method above can help you prove to an employer you're a fit for the new career path you desire, nothing beats a compelling story as to why you're drawn to this new profession. Sharing how your interests, values, and beliefs will be better served by this role can sway employers in your direction. A heartfelt disruptive cover letter that gets them at "hello" and holds their attention could be the deciding factor that makes the employer say, "Okay, let's give her a shot."
In the end, successful career changers will tell you they never gave up and they gave it all they had. You've got to be prepared for rejection and failure - and still keep going. In my experience, those that can't stand the idea of not changing careers are the ones that eventually make it.