A couple of suggestions:

1) If you have a significant amount of code behind your main form, move that code to a module.
2) Do a trace and see if you are loading other forms that you don't immediately need. You may know this already, but a form will be loaded if you refer to any of it's visible controls. If you are doing that either directly or indirectly in the load of your main form, you can avoid it by creating properties in your other forms and changing the code in the main form to refer to the other form's PropertyLet's. You can then load the other form when it's needed, and refer to the PropertyGet's for the properties you previously set.