Voting D1 is not considered a soft any more. It might as well be considered a hard claim. No mafia will miss the soft (unless they are new). It's literally the most overused thing.
A real soft is by singling the person out in a non obvious way. Maybe making a compliment to signal town (or insult to signal maf). Pointing out a color in a good or bad way. Talking about someones avatar.
Sometimes, with the avatar, I pick something I like or hate about it. Then I try to spark a conversation, I ask, and then I'm either mean (meaning they are maf) or nice (meaning they are town).
There are so many ways to do it just be creative...
Just be careful though when you signal mafia...usually they grudge and kill you anyways.