One geometry constraint is the minimum allowed line width and line spacing. These values depend on the metal layer where you put your spiral, and can be found in the technology documentation (layout rules). Typically, we want to place the spiral as far away from the substrate as possible, so we use the topmost metal layer, which usually has the thickest metal and smallest resistance. For such thick top metal, a typical value for min line width and min spacing would be 2µm. Max line width can be something like 20µm, depending on layer and technology.
The number of turns is a compromise between Q factor and inductor size. Large inductors with few turns tend to be better, but need more expensive chip area. Often, the circuit design will specify a minimum possible Q factor and then the smallest inductor is used which meets that requirement.
To get some real world values, including results, have a look at this book: "Integrated Inductors and Transformers" by Angelo Scuderi et al, CRC Press, 2011, ISBN 9781420088441