Take your time and use spot. Point the circle at different areas of the scene and watch where the meter falls. Look at the bright spots, look at the dark spots and try to find the happy balance.
Metering is all about deciding where certain shades will fall within the dynamic range. If you use evaluative, you're telling the camera to set exposure settings (or display the average exposure) based on the entire scene. How will you know where the specific area of highlights (that you don't want to blow out) are going to fall? You don't.
The key is setting your meter based on specific areas... instead of just always using 0EC (mid grey). If you're taking a landscape shot and you don't want to blow out the sky, try setting your meter (on Av) to +1 2/3 (out of 2) and locking the exposure on the bright spot using spot metering. That will tell the camera to adjust the settings so that what you saw in the circle would be exposed to +1 2/3 EC... which is near white.
If you end up with way too much shadow, you can try dropping your contrast settings and trying again.
If you're using manual mode, set it to spot and look at the bright spot. Watch the meter and change your settings so the meter reads around +1 2/3 (like before). Then, look at a dark area and see where it falls. If it's around -1 2/3... you've got a really tone right image coming. Most of the time it'll be blinking on the left meaning that it'll be pure black.
Then you'll have to make a decision. Do you adjust to blow out the sky a bit to recover some shadow... leave the shadow and potential silhouette... drop the contrast, reset your bright spot, and check to see if the dark spots are still too underexposed... or set the image off of the dark spot. You can also then know that HDR and multiple exposures might be the best way to capture the scene.
The advantage with Manual mode and spot metering is that you can analyze the scene and see where every tone will fall on the meter before you take the shot. In Av, you can still add your smarts, but you'll only have 1 reference point (wherever you lock the exposure) and everything else will fit in relatively... but you'll have to wait for the results.
A long time ago, I posted some explanations of this... there's some stuff in this post
http://www.photography-on-the.net …hp?p=1285496&postcount=13
... as well as posts to follow.
