The Strategic Genius achievement needs VH/VH. I completed itwith the World DominationCampaign as Great Britain. Finished this while the achievement ratio wasat 0.90%. Am giving my advice seeing that the ratio can probably be higher.
Recommendations:
1. Playit within a relatively short time-span so that you do not loose moral over along period of time. Start on a Friday night and finish by Sunday night. Thecampaign needs to be played out over the entire time period, 1700 – 1800. Finishingthe primary goals early will give you a message that you won, but theachievement will not unlock until 1800.
2. Playas Great Britain, France,or Spain. All three start with a protectorate. Personally I wouldrecommend Great Britain. The homeland was not invaded during the entirecampaign that I played.
3. Tryto get trade agreements then break any alliances with other nations (except theprotectorate) all within the first turn. The alliances will just lead to futureunnecessary wars. Don’t declare wars. Others will declare war on you or yourprotectorate.
4. Regardlessof how much your protectorate is hostile towards you it will never rebel ordeclare war on you. Within the first 20 to 30 years give technology to yourprotectorate. Later on you can barter for its technology with your own or withmoney, territories, etc.
5. Focuson military research early in the game. When you feel comfortable militarily,taking regions quickly, start focusing on economic research.
6. Whenother nations declare war on your protectorate always come to its defense. Neverbreak your alliance with it!
7. Tryto focus your military might in one continent at a time. Even if you haveenemies in multiple continents focusing on one will give you set priorities. Donot bother with enemies that are not worth your time, like the Barbary States.At the start of the game I would recommending all efforts in the Americas (todefend your protectorate). Then move into India and finally Europe. When Istarted the GB campaign I sent all troops to deal with the IroquoisConfederacy.
8. Ifyou are taking regions quickly then you may want to consider giving them toyour protectorate in order to move quickly and keep up momentum. Waiting tosubdue a region’s population can be time consuming. Giving a rebellious regionto your protectorate right after conquering it will make it peaceful. Yourprotectorate will be able to hold onto it (no rebellion).
9. Ifyou are moving slowly and are only focusing on one enemy nation then you canprobably keep regions as you take them. Do not give all taken regions to yourprotectorate! You will need some for an economy. In particular, do not giveregions that have a barracks, foundry, etc. You may need to practice at this tosee how you fare economically.
10. Keeptwo of the three needed regions that are needed for the protectorate to becomepart of your nation. Let your protectorate have one of the needed regionsrequired for it to become part of your nation.
11. Regardlessof how powerful your protectorate is, it will never rebel or declare waragainst you.
12. Inthe year 1797 barter with your protectorate for land. Offer all regions in theAmericas (except two of the required regions) in exchange for the one requiredregion so that it will become part of your nation. All land that belongs toyour protectorate will become yours! Extra money should not be required for thistransaction.
13. Focusingon European conflicts is unnecessary at first. Defending the homeland isimportant but expansion into Europe is not totally necessary as long as you candefend yourself.
14. Forthe Americas, would recommend taking regions that have barracks, foundry, etc.Then take remaining regions on the mainland. Finally, take the remainingislands.
15. Oncefinished in the Americas build up a navy.
16. ForIndia, first take Bengal and build up defenses. Let the Maratha Confederacy buildup its forces in that upper-right corner of India. Then, take out Mysore beforemoving onto the rest of India.
17. Ifthe Americas and India are under your (or your protectorate’s) control then youshould be good for the 50 regions requirement.
18. Focusall remaining efforts in Europe.
19. Alwaysensure that your ministers have more than three stars. Switch them out asnecessary.
20. Wouldrecommend infantry alone. Build up large armies quickly and at lower costs.
21. Autoresolvebattles as necessary. You can autoresolve every battle if needed. This helps getting through thecampaign in a shorter time frame.

Hope this helps.
Feel free to reply and post your own recommendations.