The best way to preserve your tyres is through regular rotation. Swapping the tyres around will combat uneven wear that could lead to a premature tyre change, and also evens out the discrepancy in wear between the front and rear tyres. The driven wheels will typically suffer much more wear than the un-driven wheels so regular rotation is a good idea, about every 6000 miles/6 months should be sufficient.
You’ll need to establish how your wheels are driven and make note the construction of your tyres. Ideally they should all be the same type (e.g. radial) but if they’re not, never mix different constructions on the same axle. Also, never have cross-ply on the rear with radials on the front. For front wheel drive cars, the rear tyres should move to the front, swapping sides. Move the fronts to the rear, but keep them on the same side. Do the opposite of this on rear wheel drive cars. For four wheel drive cars, swap all tyres diagonally.