Careful choice of cycling top, mostly.
I've got a Reverse Gear recumbent-specific jersey that works well on the Baron, but bunches a bit at the front on the less reclined Streetmachine. (Interestingly, they're both fitted with exactly the same model of old-style HPVelotechnik hardshell seat.)
I've de-elasticated the waist of a YACF Owayo Men's jersey, which stops it riding up (also a problem on upwrongs, but you don't end up lying on it), but it catches the air too much on the Baron.
ForceGB and Foska womens-specifc jerseys seem to work well for me on both recumbents and uprights. I think it's about putting the waistband in the right place.
Waterproofs are always a bit rubbish on reclined recumbents. I use them as little as possible.
The other thing to watch out for is rear pockets: Obviously they're just useless sweat-absorbers until you get off the bike, but you want to actively avoid any that lead to you lying on zips etc. See also waistbands of legwear, bra straps, HRM straps, bibshorts, etc. Sometimes fettling may be prudent (I've modified my HRM strap and Rainlegs so as not to end up lying on the fasteners).