The rate of a reaction can be increased by:
-using a catalyst- it lowers the activation energy and leads to less energy required to break bonds of reactants. This lower activation energy leads to more products formed with less time, hence an increase reaction rate.
-increasing temperature- the particles of a molecule move faster and undergo more collision which leads to an increase in the speed of the reaction.
-increasing pressure- means there is more particles of reactants in a reduced volume. The particles do not need to move long distances to find another particle to react with, hence the rate of reaction increases.
Using an inhibitor will not increase the rate of the reaction because, an inhibitor binds to the active site where a catalyst is supposed to act. This means a higher activation energy and thus a decrease in reaction rate.
Likewise, decreasing the concentration implies few particles available to collide with each other and that slow down the speed of the reaction.