I’ve gotten a lot of practice now setting up Windows 10 machines.  I find a few handy tools and configurations work very well.  Therefore my base recommendation for a new Windows 10 machine:

Update and Reset (if coming from Windows 7) to Windows 10 fresh copy.

Set machine name and workgroup info.

Set up machine linked to a Microsoft account.  Configure a photo and security as needed.

Run all updates before proceeding.

Install Chrome and Firefox, set Chrome as default but put both on taskbar

Install AdBlockPlus on both Chrome and Firefox

Install Malwarebytes and purchase lifetime license if possible, otherwise offer a subscription option

Install Office 365 if applicable and license it appropriately.

Set up family safety and any multiple users as needed.

Install remote access tool for support

Install Roboform if the client needs a password manager.

Set up mail – consolidate contacts and calendar to one of following:  Google, iCloud, or Outlook.com/Office 365.

Set up versioning backup to backup and protect current and deleted files for Dropbox, OneDrive, Google Drive.

Configure start menu according to client’s needs and preferences.

Redirect Documents and Pictures folder (and desktop according to preferences) to OneDrive or Dropbox locations.

Install PDF viewing and editing option desired (otherwise will default to Microsoft Edge Browser)

Set Windows 10 Update settings to include Microsoft programs.  Also turn off “updates from more than one place.”

Set up client specific programs: Firefox, Printers, special applications