Meanwhile, here are some tips on giving effective talks. Giving talks is an art that takes a lot of practice. Everyone has their individual style and perspective that they bring to their talk. That said, some generic principles and tips can be helpful in putting together a talk that is engaging, entertaining, as well as educational.
Reason out what motivated your choice of the paper(s), the topic, etc.
It is hard to overemphasize the importance of this. Right up front, bring out a clear problem statement. In the beginning, it may not be technical, for that takes some development. However, the story behind the problem should be conveyed as clearly and as early as possible. Set the problem studied in the paper(s) in the context of previous work that has been done in the field. This would be usually done by the authors themselves. Rather than parrot them, bring your perspective to setting the context. This can be done only if you take the time to understand the context.
Why is this a worthwhile problem? What applications are driving it? What is the intellectual challenge in it? Where is the challenge -- mathematical analysis, algorithm design, complexity analysis, empirical studies, something else?
List the technical contributions of the paper(s). This is intended to be an executive summary, that should make sense even to someone not in the area. Best presented in the form of bullets. (And I don't mean that sybntactically.)
Is it a first? Is it a significantly different approach to an old problem? What if anything, is novel about the paper(s)?
This is where you'd delve into the technical details of the paper(s). Again, avoid parroting the authors. Take the time to understand the technical material of the paper(s). Don't be shy about getting technical here. Be that as it may, effective presentations use plenty of well-chosen examples as a tool for conveying technical concepts and results. The key is choosing the right examples: not too simple that they fail to bring out the intellctual fun part of the paper yet not too complex that you lose the audience quickly.
This is where you'd sumarize the contributions, highlight any conclusions or lessons learned, and briefly sketch some interesting open problems.
What, in your opinion, are the strengths and weaknesses of the paper? If you were on SIGMOD/VLDB (or similar top conference) program committee and were reviewing this paper, would you recommend acceptance or rejection? Why?
A general note is that the papers were written by people you perhaps never met. But remember, the talk is yours . So, let's hear your voice and your perspective -- not just the authors' perspective -- in your talk.