Make the container smaller . If you have the same number of molecules crammed into a smaller space, then they will hit the walls more frequently with more molecules hitting the same area repeatedly, increasing the pressure on the walls. Raise the temperature . If you make the molecules move faster then they will hit the walls more frequently, increasing the pressure on the walls. We can also increase gas pressure if each molecule hits the wall of its container with greater force.
Gas pressure is due to impacts of molecules over a certain area.
The two primary factors affecting the pressure are the frequency and force of the molecular impacts. An increase in temperature results in faster moving molecules, causing an increase in both the frequency and force of impacts of those molecules. An increase in the amount of gas placed in a container results in a greater frequency of molecular impacts on the walls of that container. A decrease in the volume of a sealed container results in a concentration of the gas molecules within it, causing an increase in the frequency of molecular impacts on the walls of that container. Increasing the temperature, increasing the amount of gas inside a container, and decreasing the volume of a container, each result in an increase of gas pressure inside the container due to the reasons cited above.