Good sixth forms?Watch
If you’re interested in a really good school try Birmingham grammar schools. Last week I went to King Edwards Camp Hill Girls and I liked it there a lot but the journey for me was just too far so I transferred.
To compare different colleges in your area. Also look at OFSTED reports and league tables.
My biggest advice is to visit all of the colleges you're considering on open days and as much as possible. In terms of my chosen college, I was sold as soon as I went to visit it as it was clearly better than all the others.