Not knowing the full details such as storage, RAM, etc. it is difficult to detail any upgrades. But in general you can increasee the RAM to a maximum total of 32 GB. You can also install an SSD such as a 2.5" or NVME/PCIe SSD. The graphics cannot be upgraded at all as you have the only discrete graphics that was offered in the 5580.
@Alias007 go to support.dell.com and get the Service Manual for your system to see what parts are even replaceable. You will likely find that the CPU and graphics are soldered onto the motherboard, so upgrading those later on won't be feasible. That's been the case with laptops for quite a while now, which is why the recently released Alienware Area-51m with an upgradeable CPU and GPU design was so significant. Other than that, the only way to upgrade the CPU and graphics on systems is to buy a replacement motherboard for that system that already includes those components, but of course even then you're limited to the options that Dell actually created. You can't just install whatever component you want later, and part of the reason for that relates to power and heat. Laptops are designed to run on a certain amount of wattage and have cooling systems that can handle a certain amount of heat. So even if the CPU and GPU weren't soldered onto the motherboard, that reality would place limits on the types of components you could reasonably install.
RAM on most systems is still generally replaceable, although some systems even solder the RAM chips onto the motherboard now. If yours is replaceable, then you'd just have to see what the max supported memory for that system is. And fyi, sometimes you can install more RAM than the specs indicate. The reason is that sometimes (but not always) the max RAM spec for a system was written based on the largest module capacity available at the time and the number of slots in the system and therefore the highest capacity configuration Dell was able to validate. For example, if your system has 2 memory slots and the largest memory module on the market today for that system is 32GB, the max spec might be indicated as 64GB. But when 64GB memory modules come out later, you might find that the system works fine with 128GB. Or it might not, because sometimes there are other sources of maximum memory configurations, such as the CPU. For example, Intel's Xeon CPUs meant for servers support more memory than their Core CPUs meant for desktops and laptops. And fyi, ark.intel.com is a great website for learning the detailed specs of your particular CPU, including max supported memory. That said, even if the CPU supports more memory, it doesn't always mean that the rest of the system will. The bottom line is that if you ever want to contemplate exceeding specs, you should expect that you'll be experimenting and that success won't be guaranteed.