Complimenting her will often give you points, but only if you focus on intangible qualities like intelligence or her accomplishments. This advice may still be helpful for sites such as eHarmony or Chemistry. That should do it, I would think -- you won't always get a response, but if you stick to that, I don't think you'll turn her off in any way. You characterize yourself as having been at this for four years with no success and are asking for very specific and nonexistent rules for success. Ask one or maybe two questions.
SJB, you're asking for specifics in a field when there actually may BE no specifics.
5 Online Dating Message Tips: Examples of What to Say
NBC News did a little investigating, and found that bad weather goes hand in hand with increased activity on dating sites and apps. Answer her questions, maybe using an interesting anecdote if you have one to provide. Not too long, talk about what she wrote, and bring in a piece or two from her profile. You want to seem interested in furthering the conversation but not too pressed for it. I don't think there's anything wrong with wanting to improve my communication skills. If you have to wonder about these things, the answers are probably yes and yes.