Cook his favorite meal
Watch his favorite movie
Meet up with him and go wherever he wants to go
Surpirse him with tickets to a cinema
Lots you can do :)
its really cheesy but when I was with my ex I remember getting a sheet of paper one night and writing down 100 reasons why I loved him/what I loved about him, like just silly,funny things, his silly habits etc. Its really thoughtful and romantic, also buy a little pack of lovehearts or something,decorate it. He'll Love it. You could also make a slideshow to a song like auburn perfect two- have your pictures on it and dedicate it to him or something. Hope I helped :)
Play your favorite sport together especially those outdoor activities (badminton, tennis, billiards,etc.). If he loves video games, try playing his favorite game with him. Those things would mean a lot to him because he feels that he has made memories with you, and has established a good connection.
Well, if he really likes you and you really like him then you should just tell him. It would probably make more sense to him why you want to wait. If he really likes you then he would understand and should respect that and give you all the time you need.
There is a website that allows you to make a personalized book for someone. I think the pricing depends on how many pages the book ends up being. I did it once for an ex girlfriend and she really liked it. The website is lovebookonline.com. Just an idea!