Hills will make you stronger.
For the most part, you don’t need to run fast uphill to get stronger, especially when you’re just starting to train. Start out by including hills in some of your runs or walks a couple times a week to let your hips, glutes, and quads adapt to the stress of hills. After 2-3 weeks of “comfortable” hill work, go ahead and add one session a week of short and quick hill repeats of 10-20 seconds. This type of more explosive hill training will help you have some turnover (speed) at the end of a race. Finally, if you want to finish strong in a hilly race, do tempo (comfortably hard effort) runs of 20 minutes or longer on a hilly route, or do longer hill intervals of 1-5 minutes at your goal race pace on the race course itself (or find a similar route).
Hills will make you run taller.
When running up a particularly long or steep hill, you might notice your body goes into a chin drop-head down-forward hunch-hold on for dear life mode. To keep from doing that, try keeping your eye gaze forward instead of down and your shoulders over your hips. If you do this, you’ll run up and downhill with good posture. (Think of balancing a book on your head.) As for your feet, try keeping them in line with the rest of your body and focus on picking them up instead of putting them down.
Hills will make you more confident.
Hills are not your enemy. After running up and down hills regularly, you will gain a respect, and possibly even a fondness, for them. Once you learn how to maximize your uphill and downhill effort you will look forward to encountering hills on a run and you won’t fear them in a race. The key is to stay as steady as possible going up and as smooth as possible going down. Attempting to make a surge in either direction (up or down) will leave your muscles feeling more fatigued then necessary.