How to keep wavy hair?

Hey guys! So I have long straight hair. My routine always consisted of waking up and washing my hair and then blow drying it but I'm starting college in a few days and decided to try washing it at night instead. I woke up this morning after doing this for the first time to find out that about 90% of my hair is actually very wavy. I really love it after having thought it was naturally straight for so long but now I've come to the issue of not knowing how to maintain it. Is there a way to get the other 10% to wave up too? If I brush it out will it lose shape? Are there other products I should now be using? Any advice would be greatly appreciated!