For true safeties, consider auto-admission schools, if you have the stats.
And do your best to show interest – no school wants to be seen as a backup, especially selective privates outside about the top 20. Many of them are fierce about protecting yield. Also, if such schools have a non-binding early round of applications – I’m looking at a school like Tulane – send it then. RD admit rates seem to be plummeting, as apps rise and more and more schools are relying increasingly on early rounds to fill their classes.