Hi A. -
Here's a few ideas:
1.dont overbake. Take them out of the oven before they look done, when they are brown around the edges. Let them cool on the baking sheet - they will continue to bake while on the pan.
2. you might consider adding shredded apple to your dough.
3. Always store your cookies in a ziplock bag when they are just cooled.
I like to make peanut butter oatmeal chocolate chip cookies. I take the standard tollhouse recipe and use 1/2 cup each of peanut butter and butter instead of 1cup butter. I substitute 1-1.5 cups of oatmeal for flour. I mix it all together and then add flour until I get the right consistency. The dough should not be sticky. Store in airtight container.