Attachments are such a personal decision and crafting multiple types for a variety of different players can be problematic, hence why I am creating this guide.

First you will need 4 points of Expertise in Reverse Engineering, that's it. You do not need to worry about the Stat generated on the attachment going down, nor are we crafting PowerUps in this guide, so we do not require extra Luck or Reverse Engineering Chance.

Second make some purchases. Reverse Engineering Tool. Found under Container.

Also purchase +35 Power Bits. You will need both 2nd and 3rd Order Power Bits. Generally found under Wearable Container, look for something like "Power" or "35's".

You will need on average 24x2nd Order Power Bits, and 12x3rd Order Power Bits to complete most suits of Armor/Clothing/Weapon.

You will need harvest or purchase a little bit of Metal resource, to create Modifier Bits.

Every new player receives a Tuned Crafting Tool use the tool and switch over to the Misc Tab, there you will find the majority of Modifier Bits that can be created.

Note when crafting Exotic Attachments you must start with a Exotic Modifier Bit (Example 1H Damage, Block Chance, Heal Potency Modifier Bit) instead of a base Stat Modifier Bit (Example Luck, Strength, Agility). Exotics can be placed only on a Chestplate, Shirt, Weapon.

For this guide I am going to craft 3 different Stat Modifier Bits Strength, Precision, Luck (You cannot stack the same stat on one attachment).

Once you have 3x Power Bits (1st or 2x2nd and a 3rd), along with 3 Modifier Bits we will begin creating an attachment.
Place a 1st or 2nd Order Power bit into the Reverse Engineering Tool along with a Modifier Bit.

Right click the Reverse Engineering Tool, First Select Swap Attachment (choose which type you want to create), then right click again and select Create Skill Enhancing Attachment.

Next take the generated Attachment and place it along with a 2nd Order Power Bit and Modifier Bit into the Reverse Engineering Tool.

Repeat the Create Skill Enhancing Attachment. This will add a 2nd Stat onto the Attachment.

Now repeat the process one more time with a 3rd Order Power Bit.

The result is a 3x Stat Attachment.

Drag the attachment onto a piece of unequipped Socketed Armor/Weapon/Clothing appropriate to the type of Attachment.

If you already had a previous stat on a Piece of Armor/Weapon/Clothing, that you do not want, you can use what is known as a Socket Retrofit Kit to remove a previous stat.
Place the gear into a Socket Retrofitting Tool and select Retrofit, then you can place a new attachment on to the gear.

Hope this guide is helpful to those looking to create there own specialized Armor/Clothing/Weapon with there own desired stats.