First we built a cat tree, and it was good. Then we bought auction cup window perches, and they were even better. Then we built a catio and it was the best thing a cat could possibly imagine and their minds were blown. Then we got chickens that they could watch from these places and oh boy!!!
Yes on all these points. Although I never had to resort to use spray bottles or hissing to enforce the rules.
Use their name often (they love that). Also surprisingly sniffing things is everything to them. When playing do not let them use their nails (Just saying ouch and immediately stop playing is enough to point out you do not approve).
My cat will tap my hands when playing, but rarely use his nails, only by accident.
Make sure that there are multiple spots in the house where they can sharpen their nails. A single scratching pole is probably not sufficient.
1. Play with them at least 30 minutes a day. If they're not bouncing off the walls during this play, you're doing it wrong.
2. A catio can provide entertainment. Kinda passive, probably won't be a significant improvement.
3. Never feed them human food, even if it hits the floor. Never let them on counters or tables. Use spray bottles, clapping and hissing to enforce rules.
4. Give them safe places on high -- cat towers are cool, shelving and ceiling-height bridges are awesome.
And of course, you've already got a relationship with your cat. They'll be very slow to learn and possibly vindictive. Sorry. Better luck with your next cat.