If you plan to keep the car long term then regular maintenance is the most important factor. You may wish to consider increasing the frequency of oil changes to ensure the oil is providing the best possible protection, and having the timing belt replaced if you have not done so already. A car of this age should not be experiencing corrosion issues but you may want to prevent future problems by using a protectant on the underside such as Waxoyl or Lanoguard, and using paint protectant such as a wax or ceramic coating and covering the car in winter will help to retain the paint quality.