Yeah it is mostly just brute force memory. Mnemonics help a lot if you can think of them, and writing them also helps. The book I use for individual kanji is called Remembering the Kanji, and it uses mnemonics to teach you the first thousand kanji or so, then guides you through making your own mnemonics for the other thousand. It's very good, but it teaches you the kanji in the order best for learning all of them over time, not in order of usefulness. For instance, I know the kanji for gall bladder and legitimate wife but not the kanji for pretty. So it's not good for learning some useful kanji fast, only for if you're serious about learning all 2136.
ano hon = that book, doko ni = where. The mashita after the verb oku is the conjugation, in this case polite past tense. Regular polite is おきます, and past tense you change the す to した. か is the question particle, and turns it into a question. So "Where did you put that book?"