Ahh, I doubt I am one of the better players here. I bought Vicky 2 and AHD on sale a week before HoD came out, then bought that. I started a USA game for that week before HoD, ended it and restarted with HoD. It is now in the 1870s, and I have all 50 states, plus an extended colony in the Yukon and several extending from Liberia in Africa.
Here's what I did and how it went (not in exact chronological order):
1) Competed with Great Britian for British Columbia all the way to Crisis, then withdrew.
2) With Canada released as a dominion of GB, I keep Canada on high proirity for influence. Never able to wrench it away from GB, but made them spend a lot of influence for a long time.
3) Competed with Mexico for Oklahoma and won.
4) Colonized all the rest of the typical American Western states, Mexico got California, Nevada-Utah, New Mexico and Colorado).
5) Intervened in Texas war of Independence, won, and they joined the Union.
6) After Truce and getting Manifest Destiny, war to get all my cores with Mexico. All would have been 102 WS, so when I go 100, I got all but the 2 Texas border provinces.
7) Got the Texas Bordor provinces after 2nd Truce wore off.
8) NF for bureaucats in every colony on mainland, made each a full state.
9) Influenced and Sphered - (this is from memory, so could miss some): Mexico (after wars), USCA, Hondorus (think they got independence form USCA?), Columbia, Venzailia (sp), Ecudar, Boliva, Chile, Hawaii (later made state by decision), Haiti.
10) Hawaii and Alaska acquired was by Decision.
11) Civil war was easy. Lee moved most his troops (30k) to Pahucah area, where 3 Union Armies, all about 24k each, slid into battle with him (staggered timing), Lee was never a threat again all war long. I won the war in 2 years.