The CSM vote is our opportunity to suggest who should represent our various game styles.
CCP listens to to the CSM. Sometimes we wish they would listen more. Very occasionally I wish CCP would listen to the CSM less, but that is merely because we didn't get enough of my type of candidate on it. Think of voting as your opportunity to participate in Eve's Meta game.
Vote often. There is an improvement on the vote process from last year for those of us with multiple accounts. Once your browser has registered a vote, the next account you log in presents by default your last account's voting preference (which you can change if you want). This makes voting on your (far too many) alt accounts very easy.
The voting system means that every vote counts. Vote for who you want with a clean conscience, and apply preferences to those candidates you would settle for. You have 14 candidates you can put on your vote (out of 36), and if you do fill out the 14, then your vote will end up with someone you respect.. I also follow elections as one of my 'first life' hobbies, and it is very easy to find examples where elections are decided by a few hundred votes (Denison which I am familiar with and this list which needed a web search)
If too many voters also like your first choice, then any 'overflow' will flow to your second preference. Similarly if your first choice is not popular with others, it will flow to another more popular candidate; providing you have not let it 'expire' by not having enough candidates.
A lot of what the CSM does is covered by a 'non disclosure agreement'. We never will be able to know everything. The CSM takes players concerns to CCP, even before players know to be concerned. Some things that the CSM has been involved in:
- SMA's dropping loot again (to my personal disappointment but it makes a lot of hunters happy)
- Somer Blink
- The debate about whether K162 signatures should be delayed and how that works is from our 2 WH candidates.
- The specialised cargo holds in T1 industrials was driven by our CSM.
- The implementation of some of the siphon units.
- ESS using loyalty points.
- A certain bonus room incident.
I don't always agree with the CSM, and other games use other mechanisms to feed information to the development groups, but for Eve, to get your playstyle buffed, you want players who represent you on the CSM. Those that show up get to make the decisions. Voting is a simple way of 'showing up'.
Vote early. Vote often.
For more information about candidates, look at http://nosygamer.blogspot.com.au/p/blog-page.html
For more information on the technicalities, please read http://en.wikipedia.org/wiki/Wright_system
 Yes it is theoretically possible with only 14 votes that your vote may 'expire', but last year 99% of votes were 'used' by the 8th choice.