Don't meter from the sky; just meter from those elements in the picture which need to be correctly exposed, and let the sky take care of itself as a "background" value. The only time I give any analysis to the sky is in contrasty sunsets, averaging a slightly third-left section of sunset with the foreground.

Are you using transparency, negative/colour or B&W film? If you are using transparency, exposure will be more critical than the quite relaxed allowance of negatives.