You can use different levels of hardness for your pencils. Many times they are sold in sets of different types so you can buy a few different kinds and experiment. To a certain extent it depends on what type of drawing you want to do. Is it very detailed? Do you want crisp edges? Then use a harder pencil.
Do you like blending and smudging with your fingers to get your shading? Then use softer pencils.
An HB pencil is a good medium hardness and works well for many things.
The paper you use also affects how the pencil appears. Paper with more “tooth” and texture will take the lead differently.
You can use crosshatching to shade as well.
You can use stumps (see number 8 in the photo) to blend.
If you want realism you need to understand light source as well so you do your shading and highlighting correctly. This is essential to making things appear 3D.
I love drawing with pencil! It’s the way I learned to draw. My favorite pencil is the Tombow 3B It is my Mercedes of pencils. I love it!!!
I also recommend getting a kneaded eraser