Books are overrated.
When I got back into poker and set my sights on focusing on cash, Harrington on Cash Games was a great read. It gives a solid, albeit basic and somewhat exploitable, foundation for a good cash game. If you're in a funk, I could see it fixing some small holes or fundamental huge holes you may be missing. It's nothing earth shattering, though.
I'd suggest all of these (for an experienced player) over a book:
Crush Live Poker- Monthly subscription training site. Bart Hanson is an LA live cash game pro who does weekly video and podcast sessions. I only subscribed to the podcasts ($10ish/ mo) and listened to then on my commute, doing yard work etc. He focuses on low to medium stakes cash games. Can't speak to the video subscription (~$30/ mo?) but I'm sure it's worth it's weight in gold if you have time to watch 2 hour videos. Listening to the way he thinks through a hand and some of the concepts hes always considering opened up a lot of doors for my game. The forums are also great for posting hands you had trouble with and getting feedback. There's usually a free month trial code floating around somewhere.
Live At The Bike- Live streaming low to mid stakes cash game from the Bicycle Casino in LA. Streams live Tues and Thurs nights at 7pm pt on Twitch with replays running the other 24/7. Watching a game not too dissimilar from the one you play in is valuable. Commentary is getting even better now that they have a rotating cast in the booth. Limon is wildly entertaining and I'm a big fan, but he doesnt like to talk much strat. Doug Hull of Red Chip poker is commentating from time to time as well as some lesser known pros. They all give great insight into the game. Watch the game intently, looking for mistakes, thinking through hands, etc. Way more valuable than watching High Stakes Poker and PAD and trying to apply those to your own game, IMO.
Poker Snowie- Download the software and play around with it for the 1 month free trial. Won't get much more into detail because I could go on forever, but very helpful to identify leaks or for post hand analysis you can plug your scenario in and get a rough estimation of your most +EV line.
PLAY ONLINE- and get Pokertracker4. Racking up hands at a ~10x clip over live, tracking every decision you made over tens of thousands of hands, being able to run Leak Tracker, etc. Some people are turned off by online, and while it does play like a different game, if you can beat even low stakes online in today's pool you will crush most lives games up to 2/5 and probably the softer 5/10 games. Our minds are pretty bad about assessing our own skill and placing accurate weights on how often we choose option A over option B, etc. Playing online is truth serum for your game.
2p2- Find the subgroups for whatever stakes/ formats you play and dive in.
As for tournaments, not really my thing, but I'll try; run better >>> bink>>> profit?