How to achieve monoalkylation in Friedel-Crafts Alkylation?

Question

The methylbenzene formed is more reactive than the original benzene, and so the reaction doesn't stop there. You get further methyl groups substituted around the ring - polysubstitution. How can you accomplish monoalkylation in one step?

Answer 1

Apart from having the aromatic compound in large excess, there's very little you can do!

Answer 2

add something than can compete with the methyl groups