Experimentally, it is found that the resistance of a wire increases with its length. Conversely, the larger the cross-sectional area of the wire, the smaller its resistance. This matches intuition if we compare it to a pipe with flowing water: the longer the pipe, the harder the flow; the wider the pipe, the easier the flow. For electrical resistance, the following relation holds:
$$
R = \varrho_0 \frac{l}{A}
$$
The quantity $\varrho_0$ is called the specific resistance (or resistivity) and is a material property. In general, a material conducts electricity better the better it conducts heat.
Example: A resistance wire of length 10 cm with a circular cross-section is made of constantan and has a diameter of 1 mm. What resistance results from this? Answer: 63.7 m$\Omega$.