I personally won after 70 hours as Tokugawa clan

-If you have money dont buy Ashigaru or another cheapest army
-buy trops gradually with area's more trops mean more use of food and money
-Attack clans graduelly and have good relations with other clans,you can't have good relations with everyone so look at this one which you have good relations already
-ATTACK SHOGUN when you have hostile relations with him,or if every clan is aggresive to you,dont attack Shogun at start
-magazine army,you have much of money good,you have much area's good,if you have some food on plus i reccomend you to buying troops
-If you have 50 procent to win a battle or less you schould turn on commanding of your army
-Troops reccomendations (only if you are really bad) 1-2 Bomb ashigaru, much of Nagita Samurais,and only some of archers 1-3,
-Buy ashigaru only in critical situations
-Dont buy not needed upegrades if you dont need them if you have money you schould buy troops if you have max of troops and your food usage is on minus or 0 it's time to attack someone
-Selecting clans to attack with lot of enemies or not much of allies

If i helped i reccomend you to check my social media's and my steam profile