How to get the Tobacco to burn across the bowl.

I have been smoking a pipe for a while now. However I have observed an issue. When I smoke the tobacco usually just burns either in the middle or to one of the sides. What that leads to is uneven burn across the bowl so either I have a burner well in the middle with unburnt tobacco stuck to the walls of the chamber or to one side. I have tried to make sure that I ignite the whole surface but it often just devolves to burning in the middle or to one of the edges. Please suggest ways to deal with this issue. Thanks