You can also divine things with runes, though I know next to nothing about it. I know that you can use runes as magickal symbols for candle magick and other things, but I have never personally used them for divination and would not know where to tell you to begin. If you want more information on runes, try Runes, Alphabet of Mystery.
"Scrying" is the term that is used for looking into a crystal ball or any other surface for answers to unknowns. I do know a little about this though I'm not all that experienced in actually practicing it. I have my own little bitty crystal ball, and I also know how to use darkly colored water to do the same trick. Here's what I know: For just looking in dark liquid, you can just put water in a bowl and add food coloring until you can't see the bottom anymore. Go to a dark place and light some candles for your only light, but make sure they're not actually playing on the water's surface; that'll make a bunch of images that are actually physical manifestations. You're then supposed to use your hands (or maybe your tools, if you want) to send "charges" into the water. Your right hand is the projective and your left hand is the receptive (generally; in SOME left-handed people and a very FEW right-handed people it is the opposite). That means supposedly your left hand can bring out the images and your right can make them stay there and focus them. You should make some receptive-hand passes and look into the bowl really deeply, not like you're looking for a surface image but like you're looking into a black hole that goes down so far you can't comprehend it. You'll eventually just begin to know when to use your left and when to use your right . . . when you're scrying you just go on instinct and try to interpret images you see. Symbols as well as easily recognizable things are seen . . . sometimes your subconscious will understand even if you don't and you might dream about it, and then you'll be able to interpret it better. Supposedly the best time to try scrying is at the new or dark moon, which is a time of introspection and better understanding of the "dark" self. If you want an interesting link on scrying and how to make a "scrying glass," try this link, or try this collection of info on scrying.
There are other fields of divination; dowsing is one that is pretty well-known and popular. I have never had any occasion to try dowsing and again would not know what to tell you if you are interested. All I can say is that it is referred to by some as "water witching" and involves holding a forked stick (I think) and searching for water (and sometimes other valuable things). It's also done with pendulums, which can also supposedly be used to answer yes-no questions; you've probably heard of this at some point, using a pendulum to decide what an answer is or maybe even trying to figure out if a baby is a boy or a girl by swinging a pendulum of some sort over its mother's stomach. You might be able to learn more about dowsing at the American Society of Dowsers' homepage.
Numerology is also something that is talked about a lot and is supposedly a way of divining the future (or other unknowns). Try this introduction to numerology by Michael McClain.
I've heard of people using Ouija boards (link), reading people's palms (link), analyzing handwriting (link), analyzing dreams (link), the I Ching (link), of course astrology (link), having out of body experiences (link), and doing things like reading tea leaves (link) or interpreting blobs of hot wax dripped into water (called Ceromancy: link) or putting flour in a pan and leaving it under a flower bush to see what initials are dropped there . . . there are a BUNCH of ways to supposedly divine the future, and I am absolutely no expert; I think that a lot of them are just tricks that involve getting us in touch with the part of us that knows anyway, the part that knows instinctively based on knowledge we already have subconsciously. Find some divination techniques that work for you, and get used to using those for all your needs.