ranking a expired domain

Hello there, we do have several websites and we create new ones periodically. My question is, do expired domains improve Google ranking / or do they get faster indexed by Google?

Hello guys my expired domain is ranking on second page for main keyword, Please guide me what should I do now how to build links, and what kind of links should I make where Should I start please help me out. Should I start with social signals? If yes then where to buy them? Thanks!