The standard mods are below in reader's digest form. Search here to learn more about each choice.
1. Upgraded tires and/or wheels. Tires have load ratings of various amounts. Most people here use E rated or higher tires with load ratings of 3600 or above. There is no way to know the load rating of the tires without looking at them. Make sure you have the right amount of air.
2. Add better shocks. Stock shocks are ok, but a normal upgrade consists of Rancho 9000 adjustable shocks.
3. If you use airbags to level the truck, a common upgrade is bump stop extensions either by making your own or buying Torklift Stabiloads. Other leveling options include Timbrens or Supersprings.
4. Upgrade your rear and front sway bars. Some trucks don't even have them.
You can do any or all of these mods.