Depends on what the app is as well and how you can split the work up into stages. Are the features clearly defined? Can you work on small feature driven iterations? Or is it better to work on goal based sprints? One general piece of advice I can offer is that since you are a team of two you might not need to take an approach which has a large review based section in it. This is again purely situational. If you are doing usability testing then this can change. Also are you two working in the same location or is it remote? In the end the methodology has to suit your needs. Consider the above stuff and if you can hit us back with a bit more details I'm sure there'll be more specific answers.
As for specifics... Look into FDD. Feature driven development.
Oh and good luck with the work :)
Edit: by less review I don't mean testing and stuff. I mean formal and rigid sort of meetings every week. Sure have a proper review at regular intervals but most of the reviewing should be happening automatically with every feature/sprint completed.