The Brush Tool, Clone Stamp, Eraser, Burn Tool, History Brush Tool, Blur Tool all have brush atributes. The most important thing about any brush you use are: its diameter and its hardness. When you use any brush-based tool you will always be changing these two settings. Fortunately you do not need to go far to get them: they appear in the contextual menu (Ctrl Click or Right Click).
The other setting you will often play with is Flow in the Options Bar. This only functions if the airbrush mode button has been pressed. Ignore all the other settings you see there including the very tempting Opacity. Why? The Painting page will tell you.