Advice- Following up on 'stale' leads (potential buyers who fell off radar)

[Scott Davis]

This 'sales' question could apply to marketing FSBO, wholesaling, agents, or any related niches. But mods feel free to move if better 'forum'?

-Any tips, tricks, or encouragement on what type of attitude/approach/strategy & timing, YOU use, when you follow up on a "initially enthusiastic lead" that has gone cold ? - (specifically I'd be talking about a possible investor/buyer for one of your properties)? 

Currently: After ~5-7 days of their interest falling off, I've been shooting them a text then following up the next day around 6pm with a phone call (voicemail, commonly). Maybe a month later I might ping them once more, if their initial enthusiasm was promising. 

How many times do you try to follow up? Any advice, tips, tricks, ideal timing, even copy paste "lines" that seem to really do the trick?- as far as re-engaging? Say the lead came from facebook or your mailing list.

In the past, I've been lucky or dumb and able to take a more passive approach and primarily let the numbers sell themselves. but I know this is one of my weaknesses & I'd like to see how I can improve, even if it's only 1%. Different perspectives on how persistent/strategic other 'sellers' are in their marketing to old/stale leads, what works, and what doesn't, would be truly helpful as I work to improve my results. Thanks for any input!