FL and Commenting

I've always shied away from commenting, but i'm curious about other peoples' experiences. Are you more likely to get flagged for spam with comments? Or, if you do it properly, is it more successful than just liking and following?

Is it better to comment with emojis or simple phrases like "nice" or what?

What are your methods and what was successful?

I use only emoji's while commenting and its going good commenting around 300-500 per day.