How do I dye items?
First of all, you need a bottle of dye. To use the dye, right click on the bottle and then left click on the item you want to dye.
Items in your Wardrobe can be dyed in more colours than one. Every time you use dye on an item in the Wardrobe, the new colour is added to it. You will see a small drop down menu at the bottom of the Wardrobe which lets you select the colour before equipping it.

Where can I get dye?
You can buy bottles of dye at the Auction House or make them yourself if you are a Scholar. You can even buy dye in the Lotro store.

What colours are available?
Violet, Navy, Indigo, (Dark) Green, Olive, Gold, Rust, Red, Sienna, Umber, Black, White, Grey, Burgundy, Turquoise, Orange, Yellow, Sea Blue, Evendim Blue, Forest Green, Ered Luin Blue, Rivendell Green, Purple, Rose, Crimson, Ranger Green.
There is also Dye Wash available from Novice and Expert Tailors, which removes all colours from an item.

Dyeable area
Most items can only be dyed partially. This means that there is an area which will absorb the dye, and an area which remains the same. To check which area of an item is dyeable, use the Dressing Room Preview (ctrl+left click).

I cannot dye my item. Why?
Not all items can be dyed. To check if your item is dyeable, use the Dressing Room Preview (ctrl+left click). If the colour options for your item are disabled, it means the item cannot be dyed. This is commonly the case for unique items, pre-order items and the level 65 Helegrod sets.