I don't know for sure about the D5300 but in the past the D7000 was to lowest camera that had fine tuning of the lenses.
Are you shooting in RAW or JPEG? If RAW then you will need to sharpen in Post. If JPEG then there is a setting in your camera that you need to adjust the sharpening. If you are shooting in RAW the following will have no effect on your sharpness.
If you are shooting JPG I would suggest that you use the Fine>>Large setting and also set your camera for better sharpness.
Go into your Menus and highlight the "Shooting" menu (the camera icon)
Drop down to "Picture Controls" and click right one time.
From here, highlight "Standard" and then click right one time.
From this settings menu, increase the "Sharpness" setting to "7".
Drop down and increase the "Saturation" setting +1 notch on the slider.
Press "OK" to exit the menus and you're done.