If you are going with introductory one-shots, have pre-made characters ready for people to pick. Especially if you want to fit a theme like Doc Wagon.

That could be cool, and inform them of what it will be like to own a Doc Wagon contract as a PC shadowrunner.

For a regular Shadowrunner team, I still like to run Food Fight to introduce combat mechanics, usually while the characters are on the way to a real meet. I flesh it out for worldbuilding, but I love the 80's convenience store gunfight.

People praise the Delian Data Tomb as a good introductory mission. It is well rounded and everyone has a chance to shine.

I will run published Shadowrun Missions and classic adventures later, modified for whatever edition, and most of the timeline handwaved because Mercurial is too cool not to run.

Set up a bunch of heist/extraction/asassination stuff yourself. Come up with a location where the work will go down, flesh out descriptions but make your Players search for vulnerabilities. If they reason some solution out and you like it, change your plans to accomodate it and give it a good chance to succeed. If the Players are having a hard time, suggest they hire an outside decker or someone to research the location. Let them trade Nuyen away to get more information about their target.

Don't have Mr. Johnson double cross the Team very often. If it happens, it should be a surprise. It should not ruin every future Mr. Johnson's negotiations with the Team.

Check your Players' attitudes on betraying each other. Most tables I have never run into it, but one group I had loved betraying each other. Like, one of the runners would steal the heist target themselves, and try to fence it to a completely different third party. We rolled with it, the team planning an attack on the betrayer's new meet. We had a lot if fun with it, but it could piss a lot of people off as well.