Second question first: The Lee Changho Life and Death series is great, if you can get your hands on it. I like the large format diagrams and they seem to be practical-style problems with fewer contrived positions.
As for how to apply in your games, that's a tougher question. Some of it is free, since as your reading gets stronger, the board will just start to look different. Groups that you previously would have thought to be safe now seem dodgy. Opponent's moves that you used to think were sente will now seem to be in the wrong area.
But there are some things to be careful about:
1. Go problems have solutions. In real games, the position may not have a clear resolution that favors you. You may spend a lot of time trying to find some tesuji when there is none.
2. Time management. As reading becomes more possible, it's also possible to lose track of time on some interesting position and get into pressure later in the game.
3. Trying to live everywhere / kill everything in real games with your newfound superpowers. I'm on the fence about this. It may be good to test the limits to see what is possible. I think it is. The risk is one can start developing an overplay style, especially if it works.
