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.