Just got into this when it came to Xbox. Is there a specific meta for the veteran? Really enjoying the center line of the skill tree with the stagger shout.
Small advice: please bind your tagging/marking special enemies in a convenient button. You'll need it, tagging special enemies helps a lot.
My example shout build

1) Don't pick up reviving down teammate with shout talent. Negative (range reduction and cooldown increase) out weights positive too much.
2) For all vets, always pick ammo regen on elite kill aura. Don't pick other two, they are very minimal/worthless.
3a) Always pick regen a grenade every 60 seconds. They are your resource efficient build and for crutch/oh shit moments, because grenade spawns as loot really low. Especially High intensity shock guard modifier for a mission will have a lot of "bad situation".
3b) Kark grenade (middle tree) is good on big enemies like Bulwark, Reaper, Crusher and mini-boss Monstrosity, big damage - small explosion.
Shredder frag grenade for horde. Choose between one of these grenades to accompanying your weapon choices.
Don't use Grenade Tinkerer talent, it's a really wasted skillpoint and overkill.
4) Field Improvisation, next to auto regen grenade talent. As long as you are near or in cohenrency when ammo crate/medic pack is deployed, it doesn't matter who puts them down. They still give buffed effects.
5) A must have imo for any vets, Iron will in later of middle tree. 50% toughness reduction if your toughness is 70% above.
6) On my far right, bottom highlight one, it gives Rending to your weapon on hit. Aka, armour piercing to your attack. Brittleness is giving everyone on the team armour piericing damage to that enemy. You'll notice these two words on weapon blessing later on.
Bolter and Plasma gun don't need those.
Weapons, I'm just assuming you're still leveling, not much resources so my recommendation is for saving resource to craft for specific blessings and perks.
Perks, mostly choose between Carapace (crusher, mauler), Unyielding (reaper, bulwark, miniboss), Flak and Maniac damage bonus.
Melee, recommending using Chainsword, Catachan Mk 1 or 4, Mk2 Tactical Axe with any blessings that give you cleave on hit and damage (power) on hit. Blessings name like Wrath, Rampage, Savage Sweep, Brutal Momentum, Headtakers.
Powersword Mk3 and Mk6, are heavily required Power Cycler blessing (more Power Charge attack) to be good or feels good to use.
Try to learn each weapon combo chain, test them in Psykarium, so can get idea of dealing horde better. Also practice, block, shove if needed.
Ranged
Colour variant description, blue is most ammo - least damage (better against trash/horde), brown is the highest damage - least ammo (more efficient against speical/elite units). Grey-green is middle of the road. For whatever reasons, the grey-green version is usually the worst variants.
For Ogryn is the reverse, blue is highest damage, brown is the highest ammo.
1) Braced autogun, Agripinna Mk8 (brown one). Don't bother bracing, just hipfiring is accurate enough against sniper, tap firing.
2) Kantrael MG XII infantry gun (brown one) is the best all around ammo efficient gun. Only Kantrael guns have scope, easier to see target afar.
3) Recently buffed Vraks headhunter autogun. Any is fine, but the Mk7 (brown one) is single shot instead of 2-shot burst and it's better to build for Marksman tree of veteran (left most side) for breakpoints. I somewhat prefer these over Kantrael MG 12.
4) Accatran recon lasgun, ammo hungry weapons and must required Infernus blessing (inflicting fire damage on targets)
5) Hellbore lasguns, shotguns and revolver aren't really recommended. Hellbore feels lacklusted in their role comparing to other weapons type. Later two are more for Zealot playstyle, since their ammo reserve aren't enough for veteran.