Proper watering and feeding will give more energy to the tree increasing the leaf size and vigor of the tree. However low lighting will also cause bigger leafs. When a tree does not receive enough light it will create bigger leaves to catch more sunlight. Also it will create longer internodes. Internodes are the lengths in between leaves. If the leaves can’t catch light they form longer internodes so the branches are longer to reach further for the sunlight.
Don’t worry though, you can control leaf size. Please take into consideration fertilizing issues because they will affect the results of your efforts in leaf reductions if you don’t. However look at the base of the stem of your leaves. You will notice a new leaf bud right there. Just like a shark tooth waiting to replace a lost tooth a leaf bud is ready to pop to replace a lost leaf. If you remove the leave the new leaf will come in 1/3 smaller. Remove it again and it will replace 1/3 smaller. Don’t do it too often, or during dormant periods and you will have much smaller leaves.