To increase friction you could:

a. increase the mass of an object

b. put your objects on a wheel

c. make the surfaces smooth or slick

We would have to consider first, the word friction. This friction, would the signify on how a object would then be attracted by another, using it's own abilities that this friction, and also how strong this friction would then be. Therefore, this would actually only be handled, if the surface would then be as smooth as possible, and also, it would then have to have a slick surface, in order for a object to obtain a certain degree of friction.

Your answer: make the surfaces smooth or slick