Hi, Sandi!
I'm glad you're working trying to find a non-declaw solution. IMO, declawing should be illegal here, as it is in most other countries.
The best overall info on alternatives is here:
http://declawing.com/
Pretty much any suggestions I would give are on this site, but I'll add (which may repeat some of what's on the site: great minds think alike, LOL!):
Claw trimming is a good start. My "little one," Pete, doesn't scratch the furniture, except for a rare effort, but he's apt to use claws when I don't want him to (like playing with me), so I have to cut them super short (caution, this is only for those with advanced claw-trimming experience and the right tools--and those special claw-trimming devices for pets don't work as wel as a nice, sharp toe-nail trimmer--the ones that are larger versions of fingernail trimmers--you can find in the HUMAN nail-care aisles). He gets very annoyed when I do it, because then it's harder for him to climb his tree! I cut them blunt and short, as close to the quick as possible without damage or pain (why this is an 'advanced' technique), and I trim them often (young/healthy cats seem to grow claws fast!), usually weekly.
I haven't tried the rubber claw tips, but would recommend them over declawing in a heartbeat. You might do a web-search (which is what I do when I need personal anecdotes about how these things really work) and see if there's a cat-lovers forum where you can get some first-hand testimonials for or against.
1) Remember: cats
instinctively need to mark their territory by the scratching motion (they are actually scent marking with scent glands that are on their paws, and visually marking as well). Even declawed cats will go through the motions. They are not being "bad" or looking to do damage, it's just the way they roll.
Because of this,
a scratching surface that is more appealing than your furniture is essential. The right kind and number of scratching surfaces available, the less you cats will go after your furniture (though I personally care more for my cats than my furniture: in 20 years, I doubt I'll look back on my life and say "Gosh, I really loved that sofa of mine. It was so loving and friendly, and was so playful and fun! I still miss it")
Remember:
make the furniture less appealing, make the scratching areas more appealing.
(to make the furniture less appealing, there are some temporary aversion methods you can try: use furniture tacks to tack onion or orange mesh bags over the areas the cats like to scratch, for example. There are other suggestions, I think, on the site. If not, ask, and I'll pass some on).
Most scratching posts you will find in stroes are inadequate to the task.
A good scratching post--like the excellent ones they sell in the 'declawing' site, which aree pricey, but worth it if you have the means--has the following features:
1)
Height: it is tall enough, and/or allows the cat to stretch out (this can be accomplished with those horizontal, on-the-floor corrugated-cardboard scratchers as well, which my cats like). At the shelter, where I can observe the behaviors of cats who don't have a scratching post (though I did buy them one now, and they use it happily). The scratching marks on the wooden door frames (these cats were desperate...no place to mark!) range from about 2 1/2 to 3 1/2 feet up. A good post should be close to 3 feet tall, IMO.
2)
Material: the best scratching surface has to make a scratchy sound when used (you can test by scratching YOUR nails over it). Carpet doesn't cut it (and manufacturers who make those totally-useless, too-short, carpet-covered posts should be ashamed of themselves. I'd like to start a class-action suit on behalf of those cats who were declawed because their owners tried one of those!).
Rough upholstery material (like the rugged plaid stuff you find on furniture at 'the cabin out by the lake") is ideal. (If you're interested, and have access to someone with basic woodworking skills, including yourself, I can try to give directions for making a post like one my stepmother made for my cats...which they love...and which incorporates this material).
Sissel works well for some cats (though some don't like the rope configuration).
Corrugated cardboard (on either horizontal or slanted, like on the "Cosmic Catnïp Alpine Scratcher"---one that Pete especially likes) works well for many cats.
The
BACKSIDE of carpet can work for some (you'll notice it has a rough, kind-of-burlappy texture), but a friend of mine had someone make one for her, and it didn't appeal to her cats (outdoor cats, who no doubt have better surfaces to use).
Logs with bark, cut in half, are good, especially if you live in the country, where you have access to the logs, and a 1/2 log lying on your kitchen floor wouldn't bug you. (though most cats would prefer it to be vertical, like a real tree).
3)
Number and location, location, location.
One post won't do (unless you live in a studio appartment with 1 cat). As you notice, I've mentioned several posts my cats have. They have one or two surfaces in almost every room (except kitchen and bath), including the "declawing" post, one my stepmother made, a vertical and an angled corrugated surface, and some cat perches/trees where they also nap: all these acquired little by little, as I went from one cat to 5, and now to 4).
Cats are likely to scratch after waking from a nap (
keep a post near nap area).
Definitely put an 'allowable scratching surface"
near the furniture your cats now like to scratch. You can eventually move it, bit by bit, when they get used to it (but don't hide it in a corner, like some people do. Cats are as lazy as people are, and if they have to go out of the way to use 'the post,' while the sofa is right there, in claw's reach, guess which one they'll choose?
Cats also will just stop and scratch as they are 'passing by, so
the more 'legal' scratching places you have (and the more appealing you make them), the more apt the cats will use them, and not your furniture.
CAVEAT:
I can't guarantee 100% no scratching.
Even some of my cats scratch on other than their posts--mostly my puzzle mats or area rugs when I put them down in winter (the rugs, not the cats!)
When I catch them, I scold them: it's important, with multiple cats, that they get to know their names, then the 'scolding' is cat-specific. "No!" or "ssssss"--a hiss!'-- doesn't work to pinpoint the guilty party. A sharp "Simon!"--sorry, S.--gives HIM the message that he's up to no good. While a follow-up, sweet-sounding "Good, Simon!" tells him that stopping was the thing to do. And a very enthusiastic "Simon! Good boy! Good Simon!" when he uses the actual 'legal' scratching area reinforces things.
But, again, these are just things. Simon (oops, I've outed him!) wouldn't be able to scratch my puzzle mats if I picked them up after every use! And they are replaceable. In the grand scheme of things, these material posessions that can look a little rough around the edges are nothing.
Also, for new-to-the-home kitties, who probably don't know their names yet, or understand what "NO!" is, I like to go bilingual.

In this case, speaking "cat" and translating into English (or whatever human language you wish to use!) For "NO!", I first hiss ("hhhhh" ---almost like you're trying to dislodge a piece of popcorn from your throat: a strong breath at throat level, sounds more like their actual hiss than " sssss" does, but that can work as well if you have trouble with the ' cat accent'). Follow this with a sharp "NO!" (so, to practice " HHHH! NO!" A sharp hand clap added to this can get the message across better (and, again, this works better if you can add their name, at begining or end " Simon! HHH! No!" Just make sure to use their name in other contexts as well (when offering treats, when praising, just when talking to them), otherwise, they might associate it with discipline and not with " hey, that's me!" )
HTH! (if I could only get "credit" for word-count on posts as well as number of posts, LOL!)
Any other questions, please feel free to ask! (though you may be sorry you did!)