it is hard to generalize. The meter in your camera takes an average of the scene, center-weighted. This works well for average scenes. For starters, set the camera's meter to the film's listed speed, shoot a roll, see how you like the results. If they are consistently underexposed, set your meter at a lower speed, such as 75. When in doubt, overexpose, film handles slight overexposure nicely.
If you want more accurate metering for more difficult situations, it would be wise to learn to use the spot meter built into the camera. Set it to the spot meter setting (that switch around the shutter speed dial). If you are taking a picture of someone with a bright light behind them (window) and you want to see their face, for example, you would get close enough so the spot meter only fits in their face (spot meter reads the central round area of your viewfinder) and take the reading, lock it or transfer it to the shutter manually, then step back and take the picture.
Ektar is pretty forgiving -- when in doubt add half a stop of overexposure. But mostly, read up on the spot metering in the camera, which is very useful.