Answer:
You need to make sure the dressing is in a good place, because once its on the salad, it cannot hold really well. Well that really depends on the dressing. More liquidy dressings will make your salad soggier faster. So to help with this, you can add herbs, vegies, meat, even some fruit to help soak up the dressing a bit.
Explanation:
I'm not a 100% sure but I hope this helps.