That completely depends on what characteristic you use to sort them.
You could list the planets in order of their mass, diameter, density,
rotation period, surface temperature, orbital eccentricity, inclination
to the ecliptic, surface reflectivity, etc. Each sorting criterion would
give you a different list.
In the order of the length of the semi-major-axis of each planet's orbit,
the sequence, from smallest to largest, is ...
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
the former planet Pluto.
