Why my picture are not sharp and blur?

I tried a lot but my picture are not clear at full size 3872 X 2592 pixels.

I used even tripod with self timer so that my hand can't make camera shake. But still pictures are not clear.

what I'm doing wrong? Advise please.

Camera info:-

Nikon D3000 (DSLR)

lens used:-
18-55 mm kit lens.
Tamron 70-300 mm Li Lens.

Not been stupid but the lens of the camera might be dusty, so wipe it if that dosn't work, good luck anyway.

Without seeing them, there could be all sorts wrong…

and mostly down to you not knowing what you are doing with a DSLR…

perhaps you got the DSLR before you were ready… Or haven't learned anything…

Clean both sides of the lens so you can be sure there are no oils or smudges on it. You may need to adjust your aperture and/or the lighting.

Is your camera actually focussed? XD

Your focuseing is worng some where

If you're doing everything right, you could have uncalibrated lenses. This happens sometimes with kit lenses and third-party brands like Tamron. Remember also, that kit lenses and budget zoom lenses are not very sharp at their wide apertures. 70-300 budget zooms tend not to be very sharp at the 300mm end, no matter what aperture you use.

This is what I'd do:

1. Make sure both lenses are dust and smudge free on both ends of the lenses.
2. Set up on a tripod on a well lit subject with a lot of potential detail.
3. Put camera in aperture priority and keep it in f8.0. This should be the sharpest aperture for both lenses.
3. Take a series of shots using autofocus. Be sure to do this with a manually selected autofocus point for consistency. Check the photos to make sure the autofocus is consistent and accurate.
4. Now take a shot using manual focus. Be very careful to visually check through the view finder for accurate focus. Verify that the results match the autofocus series.

Conclusion:

This will verify at least, that it's not lens or autofocus error. If you do have an uncalibrated lens, and it's still under warranty, you can send them to the manufacturers for calibration.

There's plenty of aspects to shooting technique that can lead to unsharp images, particularly with your telephoto lens - shutterspeed too low, shakey hands, automatic autofocus point selection, and so on.

I wouldnt know since i don't have an example. But my guess is that your pictures are not focused right, so they might come out blurry.

It could be back focusing or too slow shutter speeds.

There's an option in the camera of changing the size of the picture you will be clicking.change that size and I'm sure it will help!