What should I do to prepare my car for spring?

Yes, do all three — in that order. Tire pressure drops about 1 psi for every 10°F drop in temperature, so by spring you’re probably running low. Check the sticker inside your driver’s door, not the sidewall. Your wiper blades have been scraping ice and salt for months — if they’re streaking or chattering, just replace them with anything mid-range. Salt residue eats your undercarriage, so hit a self-serve car wash with an underbody spray before the first warm rain brings the salt back up.