Factors which affect the inductance of an inductor include:
i) The number of turns of wire (N) - more turns the higher the inductance
ii) The cross-sectional area of the coil of wire (A) - the greater the cross-sectional area the higher the inductance
iii) The presence of magnetic core - when the coil is sore on an iron core, the similar current sets up a more concentrated magnetic field and the inductance is enhanced
iv) The way turns are arranged - a short tick coil of wire has a higher inductance than the along thin one.