I'm begging you to not send me only "Hi" or "How are you". It is literally the most boring thing you can start a conversation with, in my opinion. Also, I tend to ignore these people.
Be creative! Read my profile and find something to ask or to start a random convo with! I mean, that's what I usually do. Random people are my absolute favorite people on this earth!
...or if you are really terribly shy, then just say "hi" (it rhymes!!) and I will read your profile and find something interesting myself!