Right now there are basically 3 meta "roles" that you can build your mech to accomodate (solo queue only, group queue has a different mentality):
1) Long range sniper. Your goal is to outrange the enemy and therefore win the damage trade. Your weapon options are Gauss and ER LL. The ER PPC, unfortunately, is usually too difficult to hit with at these ranges.
2) Mid range poker. Your goal is to peek, alpha strike, and then duck behind cover (hopefully) before the enemy returns fire. You need an
alpha strike of at least 40 damage to trade effectively in this role unless you're very, very fast (read: light mech at 150 kph). Why 40? Because there are Timberwolves, Stormcrows, Dire wolves, Banshees, and Thunderbolts running around who can all alpha strike for more than 40 damage at medium-long range. Laser vomit is the meta, and if you can't match them in firepower then you need to pick a different role.
3) Brawler. Your goal is to use heat-efficient weapons in order to destroy the enemy at close range where he cannot easily duck away to cool down. Your heat advantage allows you to trade effectively, but only if the engagement is long enough. For this role you will need SRMS, autocannons, or small pulse lasers. You will have a hard time in the early game when most enemies are still out of range, but you excel at late-game cleanup and when pushing together with other brawlers.
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Unfortunately the SHD-2H isn't particularly great at any of these roles. Brawler is your best bet here, but you'll be fighting an uphill battle against Griffins and other mechs with good brawling quirks. The SHD-2H also cannot use Artmeis unless you leave your head's missile hardpoint empty, which kindof sucks.
Don't feel bad if you're having a hard time. The SHD-2H is kindof mediocre at the moment.
But don't get too discouraged, either. A little teamwork (if you can organize it

goes a
long way, and generally good teamwork is more valuable than a perfectly min/maxed build. Though of course you'll need
both if you're going to be super competitive...