There are a few things you can do to flirt with a girl on Instagram. First, like and comment on her photos. This will let her know that you're interested in her and want to get to know her better. Second, follow her and interact with her posts. This will show her that you're interested in what she has to say and want to keep up with her life. Third, direct message her. This is a great way to start a conversation and get to know her better. Finally, don't be afraid to be flirty! If you think she might be interested, go for it!