Playing Light Assault is one of the most rewarding experiences in Planetside 2: a class adapted to close combat and flanking which often puts you in the vanguard and forces you to dive straight into the enemy. The Light Assault sacrifices a specialized tool like that of the Engineer or Medic for a unique form of mobility, a jetpack which allows the Light Assault to reach locations inaccessible to any other class. Like the Engineer, the Light Assault carries a carbine, a weapon type adapted to hipfire and close range combat. Other weapons than the carbine rifle include the assault rifle carried by the Medic, which is a more long range weapon, or the LMG carried by Heavy Assaults, a very versatile weapon class. As a result, the Light Assault is uniquely adapted to attacking enemy flanks and taking people by surprise at close range but typically fares poorly in longer range combat.
Jump for my love
You can use your jumpjets to do things such as scale Amp station walls or hop onto the roofs of buildings in a Bio-Lab to pick enemies off or simply appear from an unexpected angle. Whenever possible, the Light Assault class should attack players from above, because much like dogs, the average Planetside 2 player is incapable of looking up. Concentrate fire on Medics and Engineers, as they are the backbone of a sustained defense. If you really get the drop on someone don't be afraid to stab them to death. It's a two shot kill that conserves ammo, is completely silent, and doesn't make you appear on the minimap. It's also incredibly funny and humiliating, just don't try to melee a MAX suit or you'll be the one who ends up being laughed at.
Need more ammo!
If you feel you must shoot try to ironsight and go for head shots if time permits. Your target will probably be too busy shooting something in front of him or staring lovingly at the sculpted ass of a MAX suit. Headshots give your enemy less time to respond and help conserve ammo, which is a serious concern for Light Assaults, who often don't have any backup closeby. If you're in a hurry, hipfire is still acceptable but just make sure to aim for the center of the enemy's mass instead of their tiny bobbing head.
I would strongly suggest you invest in C4: go all out and buy the ability to carry two bricks. C4 lets you engage a much wider selection of targets, two bricks of C4 will put a Sunderer in flames, which means it'll explode unless an Engineer gets there in time to fix it (you killed the Engineer first, right?). One brick of C4 will kill a MAX suit if it's in the dead center of the explosion and severely injure it otherwise. PROTIP: try to fly above them and drop it on them.
All the upgrades
Other important upgrades for the Light Assault are health kits. You will often fight away from any help and the ability to keep the slaughter going can be invaluable. When it comes to suit modifications the two best in my experience are the adrenaline pump and flak armor. The adrenaline pump lets you sprint faster, which allows you to get to your target faster and helps you avoid enemy fire. Flak armor lessens the amount of damage explosions do to you, letting you take a tank shell or a grenade at full health and live. I would suggest you take flak armor to things such as Amp station attacks or main tower infiltration of a three-point base.
When it comes to guns, I would strongly suggest you save up for a shotgun if you can, since Light Assaults mostly fight at close rang. The shotgun's downsides have less of an impact and the standard shotguns (the Nighthawk for TR, the Mauler for the NC, and the Nova for the VS) deal amazing damage: they're three-shot kills on nearly any class, two shots even for the NC. I would suggest slug ammo, which drastically decreases your damage falloff at the cost of smaller spread and slightly slower firing speed. Also get the extended magazine, which increases the amount of ammo your shotgun can hold by anywhere from three to four shots depending on the model. If you want to keep using a carbine I would suggest using the reflex sight because of the close range nature of most of your engagements, the forward grip to help manage recoil, and either a compensator to have even less recoil, or a suppressor if you want to be super sneaky.
Every situation its class
On the one hand, you need to remember that the Light Assault is probably the most situational class in Planetside 2, you rely almost entirely on flanking, attacking from above, and the element of surprise. Light Assaults are great for attacking places such as the three node bases: without any upgrades your jetpack can get you to the second floor from the outside. They're also great for hitting Bio-Labs: you can jetpack from rooftop to rooftop to pick people off or get behind people and blow them up. You can also use them very well in the early stages of an Amp station attack, jet over the walls and attack shield generators. Once the vehicle shields and inner shields are down though, it's time to consider switching to another class after dying a glorious death in battle.
On the other hand, you should never pick Light Assault when attacking a Tech Plant interior, you will be funneled through two small doors where defenders can easily shoot you out of the air. There's also no way to flank them until the vehicle shields are down, when you've already capped the point and secured the second floor. The exception to this is Mao Tech Plant, where the vehicle shield is located at an outer camp for some strange reason. Light Assaults are also typically very bad at assaulting one-point bases due to a vehicle's ability to simply roll up to the base in most cases. Pick Heavy Assault at these times instead. Any fight where it is not beneficial to find yourself above the enemy's position or where vehicles can easily roll up to the objective is very bad for Light Assaults.
Overall, the Light Assault is the worst class in a straight up fight. You have no special tricks once you pull the trigger, no self heal or shield but you are best suited to pick and choose your battles and catch the enemy at their weakest. Never take on a straight up fight, always have an advantage, like catching your enemy from the side or attacking them from above. At the same time, however, your life is currency, so spend it, don't be afraid to get kills at the cost of your own life. You respawn quickly and there is no penalty to dying. But most importantly, the Light Assault requires time and practice: you will die quite a few times, often learning when and what you can fight. Don't get discouraged, the reward is worth it, you will drive your enemies to paranoia and help your allies push forward while your enemies are distracted dealing with you and are losing their Medics or Engineers because you slyly capped them.