It is rare to find people who are able to define the differences between left and right without resorting to pin-pointing policies that either side might advocate for. Many bloggers, commentators, newsmen and journalists seem to not have the faintest clue what it is that separates the left from the right, only that they ARE separated and that it's their job to keep in that way.
There is also a lot of talk about principles in political speeches, though not in news media because principles aren't news; they're the unreasoned urges of the power-hungry and shameless voles that scuttle through the ancient halls of power, leaving their mess piled waist deep for the next generation to wade through. However, principles are no less real than policy, they're just less exciting; they don't change. Well, they shouldn't change - they appear to all the time, thanks to the unutterable minions of Satan we call 'politicians' (sounds so reasonable, doesn't it? "What do you do?"; "I'm a politician", the word hides so many multitudes of sin in a mere four syllables, I wonder how many volumes it would take to describe every last drop of disgust that oozes through every decent human being when faced with such fiendish, soulless, perverse creatures?)
But, yes; "left and right: what does it mean?" that's what I'm doing... put simply, the right doesn't want things to change and the left does. Hence "Conservatives" wish to conserve. They want to keep everything just as it is and, if possible, roll back any changes to how it was so it can be that again. That covers traditions, power structures, law, property rights: everything. Basically they want to keep the whip in the hands of the rich to preserve their right to tread on the necks of every pauper not already throttled by debt, starvation and unemployment - but, sorry, that's policy - the principle is, if you're on the right, maintaining traditions and preservation of culture is your driving force.
On the left, change is the principle. Again, that applies to everything; traditions and power structures, etc. This leads to the many-faces of the left, where one may find liberals and socialists and communists; all manner of Messianic hoodlums wanting to tear apart all that is holy and good in the world and rebuild it in their own twisted image, banning all religions, eviscerating the family, indoctrinating sons against fathers, burning history itself and why? Because, in the fevered minds of revolutionaries and theorists (Marx, Castro, Blair) they think they know better. No, sorry, most of that was policy, too. The principle is that the left wants things to change, in order to be reformed into something they view as better.
There is plenty more to add to this, but that's a reasonable place to start.