Upgrade your Helms and Armor first to increase your defense. Helms in particular will convey a very noticeable increase to your defense. Defense is independent from active game play and will get you a win in that category without effort as long as it is higher than your opponent's. Then, work on upgrading your Horse to increase its speed. You will get a coin bonus to getting to top speed. Finally, upgrade your Lance for more power. Each item can be upgraded a maximum of six times.