Clear communication is essential in real estate.  My clients and the vendors who help me support them expect me to be available via text, talk, and email.  My phone is considered a staple, but it is a critical tool in how I keep everyone informed and involved with every transaction that I manage.  I see other realtors who are dreaming up material for their podcasts and killing the social media "influencer" game, and I admire them for getting out there to embrace technology.  But to me, being the person to call people back (or text or email, whichever they prefer) still gives me an edge.  

Other tools that are a given:  MLS access, desktop software that allows me to create and publish ads for my sellers, email, and a great scheduling system / calendar.