Esterification reactions are readily reversible, so you end up with an equilibrium between products and reactants. With equimolar ratios, you usually get a poor yield. Instead, you should use a large (I'd say at least 5x) excess of one reagent to drive the equilibrium toward the production of product. It will be impossible to get 100% yield, but you should improve your yield. Also, since water is a product, you want to be sure that you don't have any water in your reaction flask prior to the start of the reaction, as water will shift the equilibrium away from the production of products. This means using absolute (200 proof) EtOH and not 95% EtOH.
As for temperature, you need to heat or else the reaction won't go forward. Refluxing should work fine, although I have not looked up the optimal conditions.