Some EOS 350D questions

[Jonny69]

Just got back off holiday and my photos have turned out a bit of a mixed bag and in general I am disappointed with them. Some are fantastic, but some are frankly crap

I've been blighted with dust on the sensor and mirror which is gutting to get home to find on most of my pictures. I managed to get rid of most of it but not completely, so question number one is what's the best way to clean the mirror and sensor? Any tips on keeping dust out? I only have the kit lens at the moment so it actually hasn't been off much other than to have a look inside.

I'm having problems under mixed light conditions. It's way over exposing the light parts of the picture and leaving the shadier parts very dark, whereas if I use the snappy digi camera to take the same picture the lighting is a lot more consistent across the picture. So basically I'm losing all my detail I wanted to capture. I have tried using a number of ISO settings which has helped the pictures from looking too dark overall (which I noticed the camera has a habit of doing, I'll use ISO 200 where I would normally use 100 with film etc) but the contrasting is still way too high. What can I do about it?

It works absolutely fantastically under low light and I've taken some fab pictures at night but the day ones are over exposing the highlights something chronic.