Namely, through the 19th and 20th century, make it where the Russian Empire stays a military superpower. To elaborate,
1. A military that will not only beat countries like Japan, but crush them so badly they extract reparations, among other things.
2. If something like WW1 occurs, Russia is a juggernaut that should actually be feared.
3. Main one, it never becomes a paper tiger. It can always actually back up any threats it makes.
Now, this is no easy feat, so I'll be curious what would be required.