Depends on what you want to improve it for and what yoru budget is. If for gaming then the biggest improvement would be a better GPU, The 1030 GT is not really a gaming card and something like a GTX 1650 Super would absolutely run circles around it. You could also look for a used RX 570 or 580 which are around 70-80 and 80-100 USD.
If you use it for productivity work such as photo or movies then a CPU upgrade would defienetly be the choice. The best you can do on that socket would be a i7-3770 however you probably need a BIOS update to support that and I have no idea where to find one for that motehrboard. So you could get a i7-2700K and probably wont have to worry about any issues.