Here is the guide to get T0 set for Warlock in Classic WoW
You have to start somewhere, and these sets are by far the most interesting before going shopping at AQ20, ZG, MC or BWL ... Getting your T0 set before level 60 is a good start to enjoy raiding.
if you want to find the best gear, check out our pre-raid BiS guide for warlock.
Ps: For all classes, the main parts of each set are on the same boss, namely:
Here is the list of all the pieces of the Warlock T0 set with the corresponding bosses:
As a Warlock, you will get a lot of Intellect, Spirit and Stamina from the T0 to be ready for the following dungeons and raids.
Note that the bonus set with 6 pieces becomes interesting for PVP. Feel free to pick up this bonus that is unique and ideal to get a second fear.