An alternative to veneers is a process called bonding, in which a tooth-colored material that looks like the enamel of your teeth is molded and shaped, and then hardened and polished. Bonding can be used to improve the color of a tooth, or close unsightly gaps.
Bonding is generally not as permanent a process as veneers, and can be vulnerable to the same kind of staining your natural teeth are prone to. Bonding can also be more prone to chips and cracks than veneers.
Caps are generally preferred to bonding when such a procedure isn't deemed to be effective in the long run.