So let's say you have HClO. (#10 on the front of today's worksheet in Seals.)
W: What each atom Wants in its valence. (Think about the octet rule.) Hydrogen wants 2 valence e. Chlorine wants 8. Oxygen wants 8. Since there's only one of each atom in this formula, you just add one of each number together. (If it were H2ClO, you would have 2 x 2, or 4, and so on.)
It looks like:
W: 2 + 8 + 8 = 18
A: What each atom Actually has in its valence. Hydrogen only has 1 valence e. Chlorine has 7. Oxygen has 6. Again, since there's only one of each atom, you just leave them alone and add them.
A: 1 + 7 + 6 = 14.
S: I dunno what this Stands for. It's W - A, so S: 18 - 14 = 4. This is the number of ELECTRONS that are BONDED. Since there are two electrons per bond, if you have 4 electrons, that's 2 bonds.
One last one that doesn't have a letter: It's the way to find out how many lone pairs there are. Take A - S = lone electrons. 14 - 4 = 10. There are 10 lone electrons, or 5 pairs of unbonded electrons, somewhere in this LDS.
http://i39.tinypic.com/w0m8zl.jpg <-- LDS of HClO
Oxygen is going to be your center, because Hydrogen and Halogens tend to be on the outside.
S: There are 2 bonds.
You have 10 unpaired electrons, or 5 lone pairs.
It's a bit of work, but I think it makes visualizing things easier than just guessing like Seals was having us do before.
Lewis Dot Structures Shortcut