Plan out your skill tree
See which paths are more efficient, let Path of Building advise you on which nodes are the most beneficial to your current build, observe how taking a notable passive point would change your stats.
Which gems would benefit your build the most?
Prepare your skill gem links, watch the benefits of socketing them in different items, have suggestions for the most powerful gems to add to your setup.
Build your dream items, and your current self found gear
Path of Building is able to understand most mods that can be found on items and lets you perform anointments, crafting, corruptions, and more. Set up gear sets and compare the effects of your changes.