Tech Skills

Decryption

Decryption has a number of effects: it will increase the amount of omni-gel that you gain when you break down objects that you find (supposedly, we never noticed a difference); it will allow you to decrypt secure locks to open doors and chest that would otherwise be impassible; and it will let you use the Sabotage ability to shut down enemy guns. It also increases the explosive damage from some tech effects by a percentage.

The main benefits here are the unlocking and the Sabotage ability. Sabotage will prevent any of your enemies from firing their weapons for a short period of time, but then, a short period of time will usually be all you need to kill all of them. Use this when you see enemies like Rocket Soldiers or Snipers taking aim at you.

Hard Decryption items are few and far between.

Unlocking crates and doors is the other main utility of this ability. Our engineer character maxed out Decryption, but we still found only a handful of hard-difficulty locks in the game, so you may be able to get past with only the "Advanced Sabotage" rank of this ability, which allows you to use the unlocking ability on Easy and Average locks. This will prevent you from unlocking Hard difficulty locks, but as mentioned, those are fairly rare, and don't often seem to have much better loot in them than the other crates will.

Sabotage: This is a large-area direct-damage effect. It does a decent amount of damage (although at later levels it won't deal much damage at all compared to your foes' health reserves), but also causes enemy weapons to overheat and become useless for a few seconds, which is the main point of the skill. It also has a damage-over-time effect that will cause additional annoyance.

Hacking

Hacking is marginally useful. While its passive effect reduces the recharge time on Sabotage, Overload and Damping, which is kind of useful in the absence of a good omni-tool, the AI Hacking ability that it offers you is somewhat more restricted in use.

AI Hacking: This ability lets you confuse AI and VI-controlled enemies, temporarily causing them to fire on their opponents. Enemy drones can be hacked, but they're typically not very tough to defeat anyway. Stationary turrets, like those outside of planetary bases, can also be hacked, but it's fairly dangerous to try and get close enough to pull it off. Geth can be hacked, save for the four-legged Armatures and the rare Geth Prime. It can be difficult to hit Geth that are moving with the hacking ability, though; you're best off saving it for enemies that are standing still.

Hacking foes can be amusing, but if you're playing on the normal difficulty, you almost certainly won't actually need to do so; most enemies will simply fall over when you hit them a couple of times with your weapons. On higher difficulties, though, hacking may be the best way to approach dense groups of Geth. Be sure to hold your party back behind you so that they don't shoot your hacking target, hack something, then drop back behind cover until you see the experience gain and repeat the process. It'll take a lot longer than actually shooting stuff, but it can be handy.

Electronics

Electronics is somewhat analogous to Decryption; it pairs up a lockpicking ability with a direct-damage attack. It also has the passive effect of adding to your shield capacity, which is great for light armor-wearers, and will let your character repair extra damage to vehicles when you happen to be in one. The vehicle repair talent isn't very necessary; if you drive well, you won't often lose your shields to the point where the hull of the Mako actually takes damage. The extra shield capacity will be very handy, however, especially for character that can only wield light armor.

Overload: Overload will cause a small amount of damage to the enemies near where it hits, but it will deal around four times that damage to their shields directly. It's a great opening blast in a fight, as it will make it that much easier for you and your teammates to finish off your foes' remaining shields and finish them off. On top of that, it will make anyone it hits less resistant to damage for a few seconds.

Damping

Damping, by itself, increased the radius of effect of Sabotage, Overload, and Damping by a set percentage. It's the skill itself that you'll probably want…or not.

Damping: When used, Damping (the skill) will prevent your foes from using their tech or biotic powers for a short while. This can be handy when fighting biotic enemies, but there aren't many of those, and there are almost no enemies that use tech powers on you that we can remember. It can be handy to have, but not 100% necessary.

There will come times when the First Aid skill will be your best friends.

First Aid

By default, medi-gel will apply a small amount of healing to all party members. The First Aid skill will increase the amount of healing done as you increase your proficiency here. It's pretty simple, really! Unfortunately the amount of healing applied doesn't scale well with the health totals as you reach the higher levels; it maxes out at 180 points of healing, but you can easily get over 400 points of health on your tougher characters by the end of the game. Luckily your shielding will increase proportionally as well, making it less likely that your team members will actually take damage to their bodies.

Note that if multiple members of your party have First Aid points, the skill itself uses the sum of all party member's skill. So if two members have four and six skill points in First Aid, the power will assume that you have 10 points total and give you back an appropriate amount of health.

Medicine

Medicine alone will reduce the cooldown on First Aid ability. Handy, but not incredibly necessary, as you'll probably be taking a lot more shield damage than health damage as the game goes along. Like First Aid, the amount of Medicine that all party members has is added together.

Neural Shock: Neural shock will knock down an organic enemy for a very small period of time. It also deals a small amount of toxic damage. In short, it's kind of pointless: it only affects one target at a time, it can't affect robotic or Geth enemies, the damage is negligible at high levels, and the stunning effect won't last as long as a high-level Lift or Singularity will. You've got better things to spend your points on.

Player-Specific Skills

Your player will have access to some skills that only he or she can learn; they'll be inaccessible to your party members.

Charm/Intimidate

Almost every BioWare game has allowed you to put skill points in a conversation skill that opens up new options in dialogue. They're arguably more important here than they were in the Knights of the Old Republic game, but they're still probably not critical to you, unless you care a lot about getting paragon or renegade points. Charming opponents will often let you avoid combat and will often let you obtain the maximum number of paragon points in a conversation, while Intimidate will often wind up earning you renegade points.

Note that avoiding combat as a result of talking to people will usually wind up carrying a hefty experience and cash penalty. Some missions will let you avoid fighting a dozen or so enemies if you're a skilled negotiator, but you'll often get more experience and cash (and items) if you instead choose to fight.

Spectre Training

Spectre Training is only available to you after you become a full-fledged member of the Spectres. When you put points in it, the damage and duration of all of your powers and attacks is increased, your health increased, your maximum accuracy is increased, and you regenerate accuracy more quickly while firing your weapon.

Unity: The Unity skill is handy in that it can bring dead party members back to life in the middle of a fight; normally you'd have to wait until all enemies are dead before your party members will pop back up. They'll be wounded when they come back, but you can quickly pop a medi-gel to fix that. This is useful when an enemy sniper gets a lucky Assassinate in on one of your party members before you can get behind cover.