Step 1: Leave a kind note...
-wishing him/her a nice day,
-wishing him/her good luck on test.
-congratulating him/her on a good job.
-telling him/her how amazing he/she is.
-letting them know how much you value his/her friendship.
-with a relevant quote or just a quote that you like, after all it is the thought that counts.
Step 2: Leave a flower for them to find
Step 3: Tell them something nice
Step 4: Give them a call..
Step 5: Buy their favorite candy
Step 6: Let them enjoy their favorite music
You can play their favorite songs for them when you guys are chillin' out sometime.