The way to increase friction is to make the surfaces of two objects more difficult to slide against each other. This can be done by making the surface rougher or applying more pressure to one of the surfaces. For a solid and a liquid, friction can be increased by making the liquid thicker.
There are three types of friction. Sliding friction is what occurs when a solid moves across another, such as when someone drags a heavy item across the floor. Rolling friction happens when a rolling item, such as a wheel or ball, rolls over a surface. On a harder surface, rolling friction tends to be weaker than sliding friction. So another way to increase friction, at least for rolling friction, is to make the surface softer.
The final type of friction is fluid and it is made by fluids in motion or contact between a moving fluid and a solid. A thin fluid can move easier than a thick fluid, which is why making a fluid thicker can increase its friction along a surface.
In all cases, the friction acting on a object or the force opposing the motion of the object is directly proportional to the force the object is pressing against the surface. So to increase friction it is best to increase the force of the opposing motion.