Beginner's Guide

Sections:
What kind of yoyos are there?
What are the different yoyoing styles?
Responsive vs. Unresponsive
What yoyo do I buy?
How do I yoyo?
What styles of yoyoing are there?
Where do I learn tricks?
What about string?
Where do I go to keep up to date with the yoyo world?

What kind of yoyos are there?
There's 2 major different shapes for yoyos, imperial and butterfly.

Imperial When the yoyo look like this then it's an imperial. This shape isn't in use much anymore. It's mostly only used for looping yoyos and isn't popular in any other style of play.
Butterfly 99% of modern yoyos have some variation on the butterfly shape. It's the exact opposite of imperial, as seen here. You may hear people mentioning other shapes, like H-shaped, inverted bell, V-shaped, these are all different variations of the standard butterfly shape. The shape makes it much easier to land your tricks.

What are the different yoyoing styles?

1A: One yoyo, string tricks. (example)
2A: Two yoyos, looping tricks. (example)
3A: Two yoyos, string tricks. (example)
4A: One yoyo, string not attached to yoyo. (example)
5A: One yoyo, string attached to a counterweight instead of finger. (example)

Responsive vs. Unresponsive
Modern yoyos are split into two separate classes, responsive, and unresponsive. Responsive means that when you tug the string of a sleeping yoyo, it will return to your hand. Unresponsive means that when you tug the string, it won't come back, and to make it come back you need a bind. If you're just starting out, you'll want to buy a responsive yoyo. If you've mastered basic tricks, it's time to get an unresponsive yoyo.

Lube
In general, any modern yoyo can be either responsive or unresponsive. This is controlled by putting lube in the bearing. By putting as little thin lube (YoYoJam thin lube, 3 in 1 machine oil, trumpet valve oil, sewing machine oil) as possible (so 1 drop) into a dry and clean bearing, you'll have an unresponsive yoyo. If however, you add thick lube, such as vaseline, or a lot of thin lube, to the bearing, you'll have a responsive yoyo.

What yoyo do I buy?
If you've never thrown a yoyo before, these are excellent choices:

YoYoJam Kickside/Lyn Fury: Pretty much the perfect beginner's yoyos. They play well enough to stay with you long after you learn master level tricks, but come out of the box very beginner friendly. They're also quite inexpensive and available in stores in Toronto.
YoYoFactory Velocity: This yoyo is a bit special in that it'll grow with you. It's got a set of dials on the side that you can adjust depending on your skill level. As you learn better tricks, and you learn to bind, you can gradually loosen the dials to fit your play style.

For a bit more advanced (also the best bang for the buck):

YoYoJam Atmosphere/New Breed/SpinFaktor X (SFX)/Dark Magic II: YoYoJam's metal-rimmed series have been players' favorites for years. These latest releases feature new axle designs and response systems, which greatly improve their performances over the previous models. Note: Atmosphere and New Breed have had several revisions. We recommend the latest revision with the "Solid Spin axle system".
YoYoFactory Protostar/Northstar/Starlite: This is the star of the moment. It is quite likely the best plastic yoyo ever made, and gives most metal yoyos a run for their money. The YoYoFactory Northstar is a slightly heavier version of the Protostar, and the Starlite is a glow in the dark version.

If you've moved on to unresponsive play, here's a few YoYoToronto recommendations for some metal yoyos:

YoYoFactory DV888: It's cheap for a metal, plays extremely well, and is pretty hard to beat. This is a pretty popular choice.
YoYoFactory Genesis: This yoyo is becoming a major competitor at competitions. Many top 10 places were won using this.
YoYoFactory 888X: The latest revision to a classic. The YoYoFactory 888 pioneered modern metal yoyos a few years ago, and continues to be improved every year.

What about string?
Yoyo strings are consumable. They should be replaced frequently and well before they break. Strings are most commonly sold in packs of 100 for about $10 to $15 each.

There's a ton of different kinds of strings but really, if you're starting out, there's only 2 kinds you care about, 50/50 and poly.

50/50: Half polyester, half cotton. It's soft, and lasts a decent amount of time.
Poly: Entirely polyester. Not as soft as 50/50, but plays better and lasts longer.

If you don't know what kind of string to get, just buy some highlights.

Other strings, such as GString, Chaos, Alchemy, Angel Hair, Arch View, Kitty are better for whips/hooks/suicides, but they're not really needed at all. Cotton string is used for looping, and isn't very popular anymore.

How do I yoyo?
Make it go down, make it come back up.
In all seriousness, the basics are pretty easy. Here's how you do the sleeper.

Make sure the string is the proper length. You'll want it to go from the floor to your waist roughly.
Take the slipknot at the end of the string and put it on your middle finger, in between the first and second knuckles.
Hold the yoyo in your hand such that when holding your hand palm up, with the yoyo resting in it, the string comes off the top of the yoyo.
Hold your arm like you're trying to show off your biceps
Now throw the yoyo in front of you and turn over your hand so that it's palm down. Aim for the floor about 1 metre (3 feet) from your feet.
To bring the yoyo back up, give a firm yet gentle tug on the string.
When you catch the yoyo, it should be back in the same position as before your throw allowing you to start over

For more information on beginner tricks, visit one of these web sites:

YoYoExpert, well known in the new age of video learning. Plus Andre Boulay is a fantastic teacher.
Ken's World On a String, older, but still well known. If you prefer learning with pictures and text instead of video, this is for you. The list of tricks isn't nearly as extensive however, and it assumes that you have a responsive yoyo.

You can also ask questions about tricks in this forum. There's a full complement of yoyo experts that would be glad to help you out with any problems you're having with a trick.

Where do I learn tricks?
You've learned the beginner tricks, now it's time to move on.

In person at a YoYoToronto meetup!
YoYoExpert
RethinkYoYo
GrawrD
YoYoNation Tricks Subforum

There's also other places to look like Youtube, Vimeo, and one of the YoYoToronto members runs a trick blog, One Trick A Week.

Where do I go to keep up to date with the yoyo world?
If you want to find out what's going on with the yoyo world, there's plenty of places to check out.