In addition to the parties and their national policies you also need to consider the candidates themselves. Some things that you might want to consider:
1. Does it matter to you whether they live locally as are aware of local issues?
2. Have they been in parliament before and were they a good MP?
3. Have they taken the trouble to knock on your door and talk to you/ask you what you think ans what matters to you?
4. If not 3, have they at least pushed a leaflet through your door?
You might also like to consider your constituency itself. Take a look at the the results from the last election. For example, many people cast their vote against one particular party by voting for the challenger most likely to beat them. It is called "tactical voting".
I will be voting tactically this year despite the sitting MP being a good person, not caught up the expenses scandal, being very visible throughout the last 5 years within the constiuency and fighting her constituents corner on many an occasion. She also managed to get her legislation on the regulation of sunbeds/tanning salons through.
I agree (for once!) with ravingdavis.... it is really important that you vote. It is one of the great freedoms that we have in this Country, the right to a free and private vote.
I also don't think that all politicians are bad. Whether you believe this or not, you will have an MP representing you in Parliament. Have your say in who this might be
