First, do not login to your computer with Microsoft Account. If you already did then disable Microsoft Account and create a Local Account.

Type "Privacy" in Search Windows.
Click Privacy Settings.
In General Tab set everything to Off.
Click on Manage my Microsoft advertising and other personalization info and set everything to Off. (A browser will open up).
In Location Tab, set everything to Off unless you are using one of those features.
In Camera Tab set everything to Off.
In Account Info set everything to Off.
In Contacts set everything to Off.
Calendar leave On.
In Message Tab set everything to Off.
In Radios set everything to Off.
In Other Devices set everything to Off.
Feedback & diagnostics set to Never for "Windows should ask for my feedback" and set Diagnostic and usage data to Basic.
In Background apps set those apps that you don't use to Off.

Open Microsoft Edge and click on three dots on the top right corner and then click on Settings.
Click on View Advanced Settings and set everything to Off except "Block Popo-Ups" and "Use Adobe Flash Player".

Press on your keyboard 'Windows + R' and type gpedit.msc and hit enter.
In Local Group Policy Editor navigate to Computer Configuration --> Administrative Templates --> Windows Components --> One Drive
On the right side double click on 'Prevent the usage of OneDrive for file storage' and set it to Enable and Apply. Do not close Local Group Policy Editor.
In Local Group Policy Editor navigate to Computer Configuration --> Administrative Templates --> All Settings and find 'Allow Telemetry' on the right side.
Double click on 'Allow Telemetry' and set it to Disabled and Apply.

Press on your keyboard 'Windows + R' and type regedit and hit enter.
In the Registry Editor navigate to Computer --> HKEY_LOCAL_MACHINE --> SOFTWARE --> Microsoft --> Windows --> CurrentVersion --> Policies --> DataCollection
Then on the right side double click 'AllowTelemetry' and change value to 0 and then Ok to save.

In 'Search Windows' type command and right click on 'Command Prompt' and then 'Run As Administrator'.
Go to root. (cd ..)
Run the following commands:
SC DELETE DIAGTRACK
SC DELETE DMWAPPUSHSERVICE
ECHO "" > C:\PROGRAMDATA\MICROSOFT\DIAGNOSIS\ETLLOGS\AUTOLOG GER\AUTOLOGGER-DIAGTRACK-LISTENER.ETL

In 'Search Windows' type Cortana
Set everything to Off.
Under 'Manage what Cortana knows about me in the cloud' clear all history if you were logged in with your Microsoft Account. Once again, Disable Microsoft Account if you are still logged in with it.

For better performance and to prevent memory leak in Windows disable NDU
Open regedit
Go to:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\N du
Modify "Start" Value to 4 to disable it.