Many guys who get in it start out as sporties, and work their way into it. It's a wank to get the certification needed, I'd say it's harder to get a Drivers License in BC. I know, I have done both. A decent boat, you probably already have. Get it through Transport Canada (Not hard, done it twice), and make sure it has a toilet, and at least a nice heater if it's a cabin.
THe biggest thing you need to do is ensure your guests have a good time, and that you can get people on the boat. It's the simplest of business to set up, but it's a grueling run getting people on board over time. If you are good, it happens faster.
My advice:
1) Don't bother trying to put parties together. Very rarely works, feelings get hurt, etc ec. Your job is to run the gear and boat, keep your guests happy, and put them on fish. You are not an outings co-ordinator. Been there, done that, bought the T-Shirt. There are some business models that seem to work with this, but my experience is "save your time". If you are not pulling a wage out of a day of fishing, it's a hobby, not a biz. DOn't fall into the "Cover my costs so I can fish trap". Been there too.
2) Get GOOD Google advertising. Save money on magazines, posters, etc. I recommend Ben Nickles of Guardian Media solutions. You can turn off your Google ads in a hearbeat if you don't need them.
3) Do NOT do discount trips. Easy to fall into that that. Been there, done that. Set a good price where you feel good about what you are doing, and are motivated to work hard. That way, when the inevitable rod falls over the side, or something big goes *BOOM* you don't feel bad. Discount trips will be the most expensive ones you do. I have had several phone calls, and first it's the cost of the trip, then the cost of accommodation, and wait, they have to pay for a ferry to the island, and well, that sounds expensive, etc etc. This is the price. Sorry, business is business. Besides, your fellow guides will be one of the best business assets you have, when you do not undercut them, lo and behold, your phone starts ringing when they need other boats. Fishing reports, help on the water, the odd referral of a guest is well worth not charging %10 less then everyone else. And cheaper guys are far from the most heavily booked, I find.
My $0.02 from someone who has done it.