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not sure what you are upgrading for type of things, gateway, mgmt server...
But my generic answer would be. 

Make sure that everything works correctly first, meaning receive logs, push policy etc.
- Verify that your box supports the new version. if its an appliance it would be listed in https://www.checkpoint.com/support-services/support-life-cycle-policy/

- Use CPUSE for the upgrade, make sure to upgrade the DA (deployment agent)

https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solut...

- Run the verification on the packet you want to upgrade to.
- Take a snapshot (this would allow you do a easy rollback, (more complicated if VSX) )
Image can be chosen during reboot. including the snapshot. 
- After reboot etc is done, update obejct in the smartconsole, install database, push policy
check that you get logs etc.

If you check the release notes there are step by step guide on how to do the upgrades.
I also have a few videos regarding versus upgrades scenario.

In regards to blink, i normally do the normal upgrade first and then add the GA HFA after.

regards,
magnus