ADC Preliminary Design
Depends on the sensor output impedance, frequency content, and signal range. If the output impedance is high, you need a buffer. If the frequency content is too high for the ADC, you need a low pass filter. If the signal range is too small, you need amplification.
Use a voltage divider to bring it down to the range in question, then buffer with an op-amp if necessary.
Read about the ADC's input capacitance characteristics. I've written a blog entry that will help explain this. If you're repeating your samples slowly, it's not a big deal, but rapid sampling makes this important. The sampling time before ADC conversion is also important.