I would view your photo on the LCD and check its taken correctly, if not try again. If needed adjust EV level or even go manual exposure.

Im going to have to learn how to read the histograms i think

Thosell never make sense to me...and looking at a load of charts on the back of the screen isnt photography to me, wheres the fun?!

ahh its the scientist not the artist

I do enough science at work thanks muchly

If its stacked up at one end its too bright, at the other too dark.

Actually I never use this function either, I look at the image on the rear LCD and if it looks OK I move on.*

*usually after taking at least dozen extra shots from other angles

So basically you want a nice normally distributed bell curve in the middle?

the tricky bit with the histogram is that "correct" deppends heavily on what youre photographing. Reading them is a bit of a black art

If most of the scene is black, the histogram should be mostly down at the bottom end for example. Its something you can only really pick up by experience but one tell tale sign is massive spikes at one end or the other. Except in really extreme circumstances, massive spikes at either end is bad.

My camera (and I presume most SLRs although Ive never used a Canon for long enough to find it) has an option to make blown out areas blink red on the review screen. I find that generally more useful than trying to judge by eye and the histogram.

they flash black in some modes on my canon if i look for them it helps hehe