Conservatives are mainly campaigning on a plan of cutting the budget overspend/deficit by reducing waste and increasing value for money in public services as well as decentralising them, and encouraging business and private sector growth by keeping business taxes low.
I'm voting for them, as a first time voter. Judging by recent polls I would expect them to obtain an approximately 50 seat majority in the next House of Commons.
EDIT: The latest polls are always available with non-partisan commentary on
http://www.ukpollingreport.co.uk (the site is run by YouGov employee Anthony Wells).
The Times' election site is particularly excellent:
http://generalelection2010.timesonline.co.uk with all the info on marginal seats.
Beware of news sources using a "UNS calculator" to estimate a result based on polls. Past elections, 1992 most notably, show that marginal seats often have a different swings to safe seats which makes "uniform swing" useless because we have a non-proportional voting system.