Well this might not be for all sams but I'll tell you how I play each of the 3 subs.
/war - the
omgletswhackamobhard sub
Generally as much atk/acc gear as possible. I think most of my melee damage comes while berserk is up which is every 3mins out of 5. Berserk is also +25% atk so having high attack gives you a greater increase when you use berserk. With berserk up my hits are 1.5x to 2x as much damage as normal melee hits on sky weapons and they check VT at 75 for reference. I don't really notice a difference between +atk/acc melee hits and +str melee hits so I stick with +atk/acc gear for faster TP. This is my prefered exp PT sub.
/thf - the
utility sub
Well as /thf your melee hits are going to be weaker than with a war sub and you lose double attack so your DoT is already going down. I try not to exp like this but it is really helpful for HNMs, Gods etc. I have +54 str with food and my SATA WS seem to cap out at about 1200-1250. Like Rein said the best sam WS are str modifed so stack up on as much +str gear as you can and macro it for WS.
/rng - the
fun sub
Again with this sub you lose your attack bonus and double attack from /war sub but nevertheless this sub is interesting. I basically stack as much r. acc and +agi gear on as possible and if I'm fighting anything that checks higher than T I use squid sushi. I also use JSE body, JSE legs and JSE feet for this sub as it will give you +16 WS acc for Sidewinder. I find this sub very fun for stuff like dynamis. I hit 4 Sidewinders on DL before he pwned me. Squid sushi really helps to minimize the acc issue between sam/rng and rng/anything. For exp I can get away with using a GK and still hit my Sidewinders but for sky NMs, Gods and dynamis I use an archer's knife and master commander's shield most of the time.
All I can think of writing right now, if you have more questions about my gear or whatever just post them

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75 Samurai at last, hurray!