When shopping for a vehicle that will be cheap to insure, you want to stay away from sports cars as they are likely to be more expensive. Insurance companies also look at how expensive it will be to repair the vehicle, and how much damage it may cause to another car in an accident. Vehicles with extra features like GPS and high-end audio cost more to repair, and in turn they are more costly to insure compared to base models.
Companies also look at the safety record and safety equipment on a vehicle. If the vehicle has a strong safety record and good safety equipment, it can cost less to insure. On the flipside, some safety features can increase premiums due to the elevated costs of repairing high-tech safety equipment.
In terms of age, losses are paid out on the basis of actual cash value. So since older vehicles are worth less due to depreciation, you may see lower premiums.