There are basically four solutions that do not involve extensive work on your bike: Roll up the pant-leg on the gear-side high enough to stay away from the gears.
Wear tight fitting cycling pants that don't flap.
Use braces as you have, or clips such as these to keep your flappy pants close enough to your legs.
Stuff
the pant-leg on the gear side in your socks.
Since option 3 doesn't work for you that leaves you with options 1, 2 or 4.
However, when applying the braces or clips, (or stuffing your pant-leg in your socks) are you taking care to make sure all the excess pant-leg material is collected on the outside of your leg, away from the gears?
On the bicycle side: Chainring guards might help a bit, even better is a full chainguard but these may be hard to find for your bike.
bicycles.stackexchange.com/users/424/jilles de wit
I have found that the top of and old sock over a neatly folded trouser leg works well.
Cut the top of the sock long enough to cover your pants with leg fully extended to the top of the sprocket.
The plus side is you don't ruin good socks stretching them over your pants.
bicycles.stackexchange.com/users/3083/mikes
Simple: Just take two rubber bands and stretch them around the bottom of your pants.
Done! :)
bicycles.stackexchange.com/users/5228/Sachin
When I was a teenager, the "tight roll" was in style.
Nowadays I use it nearly every day to keep my pants out of the chain.
It works better than anything else I've ever tried, is totally free, and you don't have to carry anything around with you.
http://en.wikipedia.org/wiki/Tight_rolled_pants
And here's a video about how to do it:
bicycles.stackexchange.com/users/4239/jimchristie
Get a 8 - 12" piece of velcro, loop side, then adhere a 3" self sticking hook side on the end of the inside.
Tuck and wrap.
$1.50 cost.
I have had mine for 5 years, using it almost daily with no issues.
bicycles.stackexchange.com/users/3124/Matt Adams
In addition to velcro and clips, you can use "slap bracelets."
Badge holder lanyards from conventions work well, too (but only the ones with alligator clips).
Wrap it once around, put the clip end through the closed end and pull it tight.
The clip will hold it tight.
(pics later)
bicycles.stackexchange.com/users/2302/Ward - Reinstate Monica
This product should work, Leg Shield.
Covers your pant leg from your ankle to right below your knee.
http://www.bikelegstrap.com/
bicycles.stackexchange.com/users/4756/mark
Just the act of rolling up your pant leg one or two times usually covers the problem of it getting caught in the gears.
I've also resorted to tucking it into my socks.
It seems silly to buy clamps and devices when these two "free" options are available.
Nice that it's enough of an issue that it's being brought up online.
When I started mountain biking, some of the magazines and online sites basically accused a person of being a "dork" if they didn't dress in the appropriate gear.
I don't want to wear tight padded pants just to ride my bike.
I've been wearing a t-shirt and jeans for riding for about 4 years now.
I wear them in the summer too.
I figure my legs will be more protected should I fall, wearing canvas than they'd ever be in a goofy, padded pair of semi-shorts.
bicycles.stackexchange.com/users/26726/Stacey E.
I found it easiest by taking some light weight sheet metal cut it to shape to my gear cover/guard and had a friend wield it over the cover
it helps a lot.
If u want it to match your bike paint it first.
Make sure u use heat resistant paint.
bicycles.stackexchange.com/users/7365/devan
I have the unfortunate habit of always getting my jeans stuck in my gears and end up with a nice rip on the seams.   I've used those velcro braces to keep the bottom of my pants leg close to my body but I guess I pedal too close to the gears as those get caught in the gears too.
How do I keep my pants/trousers from getting caught in the gears?
bicycles.stackexchange.com
<mountain-bike><clothing-care><7-speed>
bicycles.stackexchange.com/questions/8386
bicycles.stackexchange.com/users/3584/Mallow
There are basically four solutions that do not involve extensive work on your bike:   Roll up the pant-leg on the gear-side high enough to stay away from the gears. Wear tight fitting cycling pants that don't flap.  Use braces or  clips to keep your flappy pants close enough to your legs. I have found that the top of and old sock over a neatly folded trouser leg works well. Alternatively, just take two rubber bands and stretch them around the bottom of your pants or apply alligator clips. With regard to the bike, a chain guard may help. Solutions include tightly rolling up the pant leg or using close-fitting pants, tucking your pants into your sock or wrapping velcro, cycle clips, pant protectors,  slap bands, elastic bands or other items around the bottom of the pants, while gathering excess material away from the gears. Chainguards and covers can also be used on the bicycle itself to prevent contact.
Solutions include tightly rolling up the pant leg or using close-fitting pants, tucking your pants into your sock or wrapping velcro, cycle clips, pant protectors,  slap bands, elastic bands or other items around the bottom of the pants, while gathering excess material away from the gears. Chainguards and covers can be used on the bicycle itself to prevent contact.