I've realized (thanks to one reader's comments) that I've been gearing this blog more toward the experienced horse owner than the first timer, so I'm going to switch gears a bit and cover the real basics. I'm going to re-publish one of my original blog posts, "The Heavy Seven", since it seems unavailable in the archives.
But before I do that, here's the very best advice I can offer the first time horse owner: buying a saddle is a lot like buying a horse - get help from a professional.
1) Find a saddle either with the help of an independent fitter (or through one who reps multiple saddles) or through a reputable shop with a good inventory and a good fitter. This will allow you access to saddles from a variety of saddle makers, which I believe is vital - there's no one company out there that makes a saddle that's perfect for every horse and rider combination, so limiting yourself to one company may not be the best idea. Working with a good fitter should also cut way down on the trial and error process, since the fitter can direct you to the tree shape, tree width, and panel configuration that would most likely work for your horse.
Now, I hear you all asking, "How do I find a reputable fitter?" Word of mouth is usually the best way - if someone's "street cred" is overwhelmingly good (or the reverse), there's usually a reason for it. And while there are companies, associations and schools that will certify people who pass their courses, I'm going to don my flame suit, brace myself, and make a bold statement: it's my belief that not all good fitters are certified, and not all certified fitters are good. Some certification programs, like the Society of Master Saddlers or Mike Scott's program, are very lengthy and detailed and require prior knowledge and experience, and some are not; many of the certification programs offered by saddle companies are geared toward teaching their reps to sell and fit their saddle rather than saddles at large. I'm not certified by any association, though I have learned from certified fitters, and regularly have certified fitters refer clients to me. My mentor (and hero) Patty Barnett - who does all the big scary repairs that I don't have the equipment or know-how to do - spent 5 years apprenticing with Gary "the Saddle Dr." Severson, and she's not certified, either. So my advice would be to put more store in reputation than in certification.
2) Make sure you can try the saddle before you commit to buying it. Some shops will offer you a one-week "ride it like you own it" trial. Panther Run Saddlery (that would be me) is one, and Equestrian Imports is another. We want you to put your fittings on the saddle and really ride in the saddle - take a lesson or two, go on a trail ride, whatever it is that you do. You simply can't tell if a saddle's going to fit just by plunking it on your horse while s/he stands in the cross ties. What looks fine there may be a whole 'nother story when you're up and your horse is going, so remember: try before you buy.