Suggestions Developing SEM Plan for Phone App

I am new to the WF and was hoping to get some suggestions developing a general SEM plan with the goal to get as many legit app downloads as possible.

Quickly, a little bit about the app: it is an android/ios where users can find jobs in their area using a new framework (cannot go into detail here). The app is not my idea, I am simply going to help market the app online with the goal to get as many quality downloads as possible. The app is still in beta and is only supplying job info in 1 major city in the US. The available job market will grow into other cities as the app is more refined. Jobs can only be applied for using the app.

Which technologies should the company consider for targeting perspective users?

My List and thoughts:

1. AdWords - What is the best way to utilize AdWords (Geo Targeting, display network, YouTube)? Are there better ways or insider tricks to use AdWords more effectively?

2. I am a big fan of re-marketing using AdRoll and Perfect audience. My idea would be to re-market the job category the visitor browsed (ex: Accounting) to them across the web. Is there a better way or better technology to do this?

3. What is best way do find relevant keywords and related interests? Tools, tricks?

Are there any tools or other pieces of a sound online marketing plan I am missing and need to also add? Any help from the group would be very appreciated.

Thank you,