A lot comes to mind when responding to this. I'll start here.
You probably can't make someone love fishing. Some who were born in a family with deep background in the sport just would rather do other things, and some who have no early age tie-in become the most fanatical folks of all. I'm sure you do, but show your own excitement when planning your trips. It's contagious.
Big lakes, ponds, rivers, creeks, oceans all have their own magic. Personally, I spent many a morning wading/floating many of the creeks/smaller rivers in Missouri and have grand memories of those days. An ocassional change of scenery can be good.
Start with quality tackle, reasonably light line, and baits that can be cast easily with tackle that is used (and that will be productive in catching the target species). Your partner needs to have their own equipment/tackle box.
Discuss the when, where and why regarding your fishing decisions and encourage your partners suggestions. Discuss the particular waters you are on, the fish in those waters, the forage base, the seasonal movements and patterns.
Relish the successes and enjoy the more difficult trips. Take pictures and share them. Recall those special memories in other situations.
See the sun rise! Watch the weather change. Share the seasonal changes in the world around you. Observe wildlife (not talking about the human summer crowd here). And most of all, try to instill an awareness of any on water details (fish activity, bird feeding, weather conditions) that can put you on fish.
Lastly, follow the rules and teach respect for the land, water and others that you share it with.
All I got.