How To Reverse Engineer
First, you need a "power bit". A power bit comes from looted items with a stat (like a "chetplate of agility" that you loot from a stormtrooper that has +18 agility as a stat on it). You put the Chestplate of agility into a "reverse engineering tool" (which can be crafted very easily using your Weapon/Droid crafting tool & standing near a Weapon/Droid crafting station for best results). Statted items drop from just about every npc in the game. Higher level NPCs drop higher level statted items.[/size]
Then you need a "modifier bit". Modifier bits are the result of 2 "Junk items" (example: software module and hyperdrive unit). You put 2 pieces of junk into the "reverse engineering tool" as I described above, and reverse engineer them; this creates a modifier bit. Junk items also drop from just about every npc in the game, meatlumps are a good source for these (they spawn in coronet on corellia). all "junk items" are the same, there is no "level" on junk items. However, higher level npcs drop higher level junk (which meatlumps and low level npcs do not drop). Higher level junk usually makes higher level "modifier bits".
The above link will tell you which specific "junk loot" makes specific "modifier bits."
Now once you have a "power bit" and a "modifier bit" you can put them both into the "reverse engineering tool" and select "create skill enhancing attachment" and it would make an attachment which you drop in your armor. The stat/power of the "Skill enhancing attachment" is based purely off of the strength of your "power bit" and the stat on the "modifier bit".
Now let's have an example:
You loot a "Chestplate of agility" from a stormtrooper which has +18 agility.
You RE this and it makes a power bit with +18 power (or more than 18 or less than 18. LUCK and RE CHANCE make it higher than 18, the more LUCK and RE chance you have, the higher the power bit will reach. if you have 0 luck and 0 RE chance, you will probably LOSE power, meaning it would turn into a +17 or +16 power bit).
Now you have your powerbit. Now we need to make a modifier bit. Let's say you have a "Chassis Blueprints" junk loot, and a "medical console" junk loot. If you RE these 2 specific items together, you get a LUCK "modifier bit".
Now we take our +18 power bit, and our luck modifier bit, and put them into the reverse engineering tool, and it makes a +18 Luck attachment which is ready to be dropped in your armor (if you're an armorsmith) or clothing (if you're a tailor) or weapon (if you're a droid engineer). To drop an attachment into your armor/clothes/weapons, it requires your equipment to have 1 socket.
How to RE (advanced):
So you made your attachment with +18 luck, but now we want to add Agility and Con to it too! No problem. Each attachment can have up to 3 stats (3 *different* stats).
Well here's what you need:
A 2nd order power bit (for adding the 2nd stat). A 2nd order power bit is simple to make. Instead of REing a "chestplate of health" all by itself, you add ANOTHER piece of statted loot into the RE tool ALONG WITH the "chestplate of health".
And a new "modifier bit" (with a different stat).
for example:
"chestplate of health with +18 con" + "boots of luck with +10 luck" + Reverse Engineer them together = 2nd order power bit with +18 power (or more or less as I described above).
Now, you take your pre-existing "skill enhancing attachment" (which we made in the newbie section), AND the 2nd order power bit, AND another "modifier bit" but with a different stat than the "skill enhancing attachment" has. Reverse Engineer these *3* items together and it creates a NEW "skill enhancing attachment" with 2 stats (stats based on the power of the powerbit, and the stat on the modifier bit).
it's simple.
Now let's say we wanted to add a THIRD STAT to that "skill enhancing attachment".
Well you need a "3rd order power bit". This is exactly the same as making a 2nd order power bit with 1 important exception: You need to have an item with 3 or 4 stats on it example: "shirt of the Jedi" that has +15 con +15 agil +12 stam (3 different stats).
you take your "Chestplate of Stamina with +18 stamina" and put the 3 or 4 stat item in the RE tool along with that, then reverse engineer them together and you get a "3rd order power bit" with +18 power (or more or less as described above).
now you take your "skill enhancing attachment" which has 2 stats on it, AND the 3rd order power bit, AND a new modifier bit (with a different stat than the "skill enhancing attachment". RE those 3 items together and now you have a "skill enhancing attachment" with 3 stats that can now be dropped in your socketed armor/shirt/weapon. This is the final product and you cannot go any further with it.
Tada!
Guide to making high-end power bits (elite):
Well this is more difficult. You need to have a statted piece of loot to start with, you normally want to start with something high-end (for example, a chestplate of agility with +24 agility). And you need to be pumped full of "Luck" and "reverse engineering Chance". RE the +24 item and you will get a power bit with +28 or +27 or +26 power (stats are based on your luck and RE chance mods).
+28 not high enough on your power bit? Want to get it higher? it can be done... very time consuming, but it can be done.
Lets say you're an armorsmith and you have a +28 power bit, but you want to get it up to +35 (the maximum).
Well first you need TONS of "junk loot". Probably a few stacks of 50 wouldn't hurt. because you need to make a lot of "modifier bits". The modifier bits you need HAVE to be 1 of the 6 basic stats (con, agil, stam, str, prec, luck). and CANNOT be anything special (like "rifle action cost" or "engine experimentation" - more on those later).
Now you need to make crates of socketed armor. Bracers are the easiest, just set up your factory to make 300 bracers.
Once you have your modifier bits and junk loot, and you have pumped up your luck and RE chance mods, you can get started.
take your power bit and modifier bit and make an armor attachment out of it. drop that armor attachment into one of your socketed bracers. RE that bracer and get your power bit back. the power bit you get back *MIGHT* be higher, or it might be the same. (if you have no luck/RE chance mods, then it will be lower, and you might as well stop reading here because it would be impossible for you to achieve +35).
Let's say your power bit is the same. Repeat. Repeat. Repeat until the power bit goes up to +29, then repeat repeat repeat until it goes to 30.. etc etc etc all the way up to +35. This process is very time consuming and can probably take upwards of 100 tries (that would be 100 bracers). I said it was difficult and I'm not lying. This is currently the only known way to boost the power on an existing power bit.
That should be all the information you need to get started. Just keep trying, experiment using garbage loot you buy on the bazaar for 5k. You will get the hang of it in about 45 minutes of REing.
A guide to advanced "modifier bits" on the way.