When I set up the balls, I put the first and last ones on the rail, to make it a little harder. With the first ball on the rail, I set the cueball at a shallow angle and use a little draw.
After about three hours of practice, I noticed a narrow triangle of chalk marks on the cloth in the area where I set up for the first shot.
At first I was trying to stun balls 2 - 5, but found that I was often going to the side rail. Duh. I'm having more success slow rolling them with some side, or sometimes a drag draw. I've found that the sharper the angle, the less outside you should use, or you will end up on the side rail, unless you want to use more side and go two rails.
Balls 6 - 8 may require just natural roll or with a hint of inside, but that's if you get perfect on them. Many times I'm straight in on them, or what's worse, just slightly above straight in. You have to stroke it with low outside to come back to the rail and spin up table a bit, but it's real easy to overdo it.
One of my favorite shots on the lower number balls is when I don't quite have enough angle to roll it, but it's too much angle to draw back and up, so I slam it with high outside. The cueball swoops forward and down to the bottom rail, then comes back off the rail on the same path it took going in, spinning into position like a top, if you're lucky.