When it comes to individual skill sets in Mixed, probably the biggest challenge in adapting to this style of play is being able to accommodate the team's greater range of athletic abilities. Imagine a scale ranging from one to seven, with one being the least skilled and seven being the most skilled. In the Women's division let's say you have to account for a range of 1-4 (at an elite level, probably just 3-4), and in the Open division you have to account for a range of 4-7 (at an elite level, probably just 6-7). In Mixed ultimate you have the whole range 1-7 (at an elite level, probably falling mostly around 3-4 and 6-7).
This means that in split second decision-making, whether you are a thrower, cutter or defender, you have to first recognize what range of player you are dealing with, and then make potentially large, yet precise adjustments in order to successfully complete a play. In single-gender ultimate, you are always dealing with a much smaller range and therefore the adjustments you need to make to account for different levels of speed, strength, and quickness from one moment to the next are not quite so drastic.
For men, throwing is likely to be the skill that will make or break Mixed success. Guys need to develop their entire arsenal of throws (breaks, hucks, dumps) so that they can put the right amount of touch on it, making it catchable for a woman. Your offense, and to a large extent your team's success, will depend on this. Knowing how to use more finesse rather than just brute strength takes a lot of practice and kinesthetic awareness, but it's part of being a team player and is something men in Mixed must do.
Field awareness is also huge for men. As a downfield cutter, men must avoid thinking that they need to save the day whenever a woman goes deep. If the throw is meant for her, let her go get it. By running into her area, instead of helping you are bringing in another defender and making it that much more difficult to make the catch. Alternatively, cut under, bring your defender away from the play and become a second option for the thrower. As the thrower behind the disc, you have to be extra aware of males poaching off on women, whether the threat is a defender who just cleared from an in-cut or a deeper defender looking to snag himself a huck. Know how your genders are dispersed on the field at all times.
For women, the situation is a little different. While having the throws to accommodate men and women is a necessity, it is easier for women to develop these than men. I know that as long as I use some semblance of timing and technique, there are men on my team that I will never overthrow no matter how hard I throw it. In addition, being more similar in physical ability to the rest of the women on my team, I will naturally have an easier time hitting their cuts than a man would.
I think the most important adaptation women have to make to the Mixed game is being able to play at the same intensity level as the men. This might not sound all that hard, but if you've never shared a field with men before, you'd be surprised how easy it is to get lost and become invisible. You really have to tap into your more aggressive and competitive tendencies and make yourself a presence on the field.
How you choose to do this, whether through being vocal, or by giving your teammates a look conveying, "I'm going to kill you if you don't throw me that disc," or by being really physical on defense, it is a matter of personal preference and knowing your strengths. But regardless of how you choose to do it, you have to figure out how to be big on the field despite a relatively smaller physical stature. Make them recognize that you are a factor and a contributor.
Having retired from figure-skating, Kris Kelly has found time to help create, build, and lead one of the most successful Mixed teams in the world: Boston's Slow White. As an aggressive defender and cutter, Kris spends here spare time getting surgery and dispensing copious amounts of nutritional/preparation knowledge. (Check out her presentation on tournament prep at this year's UCPC).