Avalon Code is not the quickest or easiest game to play, but I like it that way. First there's the information collecting. Each area gets its own page in your book. A new page is automatically created when you enter the area the first time. You'll see on the bottom right a score for the area listed as 500/1000 for example. This means that you've got 500 points of hidden things to find. Luckily they are usually around 100 points each, but that's still a lot to find. Some of them are obvious things, like examining a clock or a bookcase. Others though, like a tiny clump of mushrooms that you can't see, just require you to run around hitting (A) and hoping you find things. Unfortunately, this method gets a lot harder after you learn "Judgment Link," which is also called with the (A) button. You'll run around trying to bounce a non-existent enemy in the air when you don't find anything to inspect.
Then there's the fighting to consider. Normal enemies aren't very hard to beat, especially after you take away their attributes. As I said before, you need to scan everything in the game. Everything that you scan, including people and enemies, has attributes. You can take away attributes to make enemies weaker. You can even add attributes to make people and weapons stronger. Some attributes can't be removed though. You'll need to figure out how to cancel those attributes out if you want to be rid of them. So you have some options as to how to play. You can run around and kill things as they are which means it might take longer to kill them, or you can edit them and then kill them, which does take a little more time to edit but less time to kill.
You can also scan the bosses (which I highly recommend so that you can use their attributes) to make them easier to kill. You don't get very many hit points in Avalon Code though, so you will still need to be careful on some bosses even if you've taken their attributes out. Luckily, dying really doesn't hurt much in this game. The game autosaves at the end of boards, so if you die, you won't have to repeat very much at all.