I agree with the OP who suggest working on your technique before looking at new lenses. Do you understand the exposure triangle? [shutter speed, aperture, ISO] Each of these settings will affect the other, so it is important to know what each does and how they interact. How you hold the camera can make a difference for camera shake.

Also, before buying a new lens, you will need to know what will be the best choice for what you want to do. For instance: Portraits, Landscapes, Wildlife, Extreme Closeups [Macro], each have their own focal lengths and apertures that work best, and different lenses also will have a "sweet spot" where they have maximum sharpness. Good glass is generally more expensive as well as heavier. I like lenses that offer the maximum aperture of f/2.8 which makes it good for low light as well as daylight or studio lighting. Another factor is focal length range. Prime lenses are generally the sharpest, but less convenient than a zoom. For zoom lenses, the smaller the focal length range, the more likely they are to be sharper throughout most of their focal lengths. These days, there are a lot of "super-zooms", and new technology has made them much better at sharpness over their focal lengths. But for older zooms the theory still applies.

My recommendation is to work on your technique and understanding of exposure settings, then before deciding to buy a new lens, decide what you want to use it for, and then research lenses which would fulfill your requirements. Don't overlook the use of FX lenses on your DX camera. Just make sure you know how the crop-factor will affect the image. This will add a lot more lenses to your possibilities!

One more thing: when responding to someone's post, use the "quote reply" so it is clear who you are speaking to!

Hope this helps.
Susan