1. Feeling "best buddies" 

2. Misses you.

3. Text mate / chat mate

4. Gives you present

5. He/She invited you to their family reunion

6. He/She dedicate one particular song to you

7. Ask you to a movie date

8. A little possessive 

Be careful to handle with this kind of relationship. He/She maybe sending you a mixed signals and not because he/she like you.

Don't assume. Ask him/her the real score.