I think you are going to have to explain what you mean by "more powerful".
From the standpoint of physics, "power" is defined as "energy per time". So if you mean "more energy released by the reaction per unit of time", you have two ways to do this: increase the amount of energy and decrease the amount of time. These two things are related, though. You might say, well I can just increase the amount of reactants. More reactants means more energy produced, so more power. It's not quite that simple, because rate depends on reactant concentration, and that dependence varies from reaction to reaction. So, while more reactants may mean more energy, it's not necessarily the case that more reactants means more power over every time interval. The best way to increase power may be to decrease the amount of time reactants take to react, and one way to do that is, as noted by the previous poster, to increase the temperature. An increase in temperature will also affect the amount of energy produced per amount of reactant, though, and that may be for the positive or negative depending on the reaction. So it is entirely possible that, while increasing temperature may decrease the time over which energy is produced, it may also decrease the energy produced, so the change in power may not increase like you think it does. An even better way would be to use a catalyst. A catalyst speeds a reaction up but does not, to a first approximation, change the amount of energy produced or consumed. It only changes the amount of energy to get the reaction going. So, to increase the power of a reaction, use a catalyst. Is there a catalyst for an acid/base neutralization reaction? The thing is, neutralization reactions are already pretty quick, so you may have trouble finding something to make them quicker. You may take other mechanical steps, like making sure the reaction is well-stirred. This isn't really a catalyst but it will ensure the reaction rate is not diffusion limited. So, theoretically this can increase the power production of the reaction, although gains may be modest.
Of course, maybe you have something else in mind when you talk about "more powerful"?