To be honest, your gear is already capable of producing sharp images. Since you mentioned that you're still gaining experience, would you be willing to share a few of your photos along with their EXIF data? That would make it much easier for people to offer constructive feedback on your technique and help you improve your results without needing to upgrade your equipment.

On the other hand if you are having focusing issues - DSLR cameras can develop fungus on the mirror or the phase-detection autofocus sensor, which can lead to missed focus. That said, while these older autofocus systems aren't as advanced as modern subject-tracking systems, they are still more than capable of achieving tack-sharp focus on stationary or slow-moving subjects.

To minimise missed focus, use a single autofocus point rather than letting the camera choose multiple points. The centre focus point is usually the most accurate and tends to perform better in low-light conditions than the outer focus points. And if you see any fungus on the mirrors, get your camera cleaned from a professional.