Duo can be a lot of fun. It is the event that we have seen to greatest evolution in over the last five or ten years. Students are being given great deals of latitude with what we have considered our forensic norms and unwritten rules. Lots of people are pushing the envelope. Sometimes that good, sometimes its not.
Duo is still dependent on a solid script. Finding good scripts is particularly challenging. Female-Female duo are usually not that strong. It has nothing to do with female interper's abilities. It seems that writers have a difficult time producing good strong female scripts. Academy award winning actresses have been claiming that for years.
In general female-male duos tend to be the strongest. The gender dimension seems to add to the complexity of the story line. There are more tensions and social expectations (and thus potential violations) in male-female relationships. Thus the scripts can be more complex and challenging.
There are many factors that come into play when you are looking for a good duo. For example, you may want to do a duo with a specific person. That means you have to find a script that "fits" each of you. Certain aspects of the physical appearance of the people involved must mesh with the scripted characters. The two of you must be believable in your roles. You must have the chemistry that it takes to work together. Remember, duo is a competitive interp event, not a dating service. You might really, really, really like someone. That doesn't mean they will make a good duo partner for you. Find the script, then find the partner.
I suppose you should know now. I am not a big "tech" coach. If you want a duo with lots of touching and taking your partner's book and blocking that looks like interpretive dance, you might want to find another coach to work with on it.
Here is a paper that was presented at the 2003 National Communciation Association convention about blocking and duo. You may find it very helpful. The authors have eight national Duo final round appearences between them so they know from whence they speak.
NCA Paper on Blocking Duos
Samples of What Duo Scripts Might Look Like