Depending of your PIC, your ADCON, ANSEL setting have to be set to make AN0, AN1 as analog first. Your sampling time and clock source look fine... even if they are way too slow. Too slow is still better than to fast, so it's not your problem source here.

Your pot have to be connected between Vdd and Vss. The wiper goes to the PIC input. It's value must be equal OR less than the maximum recommended by your datasheet. It's a good idea to filter the POT output with a capacitor (10-100 nF)