Well for any magazine to be successful it needs to have decent topics of interest in every issue, it needs some decent headlines that catch the eye right away and the articles need to be written properly and professionally.
I would have a focus on big name curlers to draw readers and attention, also focus on local clubs around the country. Most people who would buy a curling mag would curl themselves so local club curling is a must in my opinion.
Curling isn't explosive or splashy, so you'll find it difficult to talk about the big name curlers all of the time, there won't be scandals or many publicity events like movie stars, so you can't just have a bunch of photos and a few lines of captions like other mags. Focus on items of interest like new rules coming out, old strategies that are tried, tested and true. Inform people of new strategies and different game types like skins etc.
Try to go broad with the topics but still keep them interesting and informative. You can keep track of good teams from around your country that haven't made it big yet but have the potential to do so.
Also to get a mag going you'll need sponsorship, look at the big curling matches in the country and try to get a sponsor that people will recognize, also don't flood the mag with tons of small ads, that really turns people off. If they have two paragraphs to read on every page and all of the rest are ads, that's a good way to kill off customers.
Use photos of course but they have to be of decent quality, a poor photograph is hard to look at these days with all of the high definition stuff we look at all day. Also remember to have a catch but NORMAL title for the mag, you won't be getting a lot of young people buying it, most curlers are older, make the title something that they won't be embarrassed to read or say. Word of mouth goes as far as a million dollar marketing budget.
Use your head and get lots of idea from everyone you know. Don't get emotionally attached to ANY idea, slogan or company. This is a business venture, if you think of it as a hobby or extension of your personality, then stop right now and don't waste your time. Only focus on decent, fresh content and professionalism. That's the only way small businesses even have a chance of starting. Also in the digital age, with all of the big newspaper companies struggling to stay alive, a small mag about curling...? If I had to guess if you would be successful... I would say "no". The paper publishing industry has been shrinking considerably for over a decade and it's only going to get smaller.
Maybe an online mag would be a sustainable choice but remember, no idea is 100% bad, you can always shape a poor thought or suggestion into a winner, be positive and always be thinking about what to do next. If you aren't "current", you're the "past".
Good luck!