Ahjuna
Neophyte
To start...you have to have at least 50 skill points in both lockpicking and detect hidden before you can train remove trap. Once you have 50 in both, head to the thieves guildmaster just SW of West Britain Bank and you can train remove trap close to 50. If she won't take you all the way to 50, you can go to Buc's Den to the thieves guildmaster there and he might take you a bit higher. Once you have trained remove trap (even just one point), you can drop detect hidden and/or lockpicking if you don't need them. To train remove trap the most efficiently, you need to also train tinkering. Ideally you start your training with 50 in remove trap and 58-60 in tinkering. If you need to raise tinkering to get it up to 58-60, just make lockpicks to get there. You want to keep tinkering around 8-10 points higher than remove trap so the traps are just difficult enough to gain from. The supplies you need include one crate or chest, iron ingots, and crossbow bolts. The ingots will have to come from a player vendor but you can get the crossbow bolts from the provisioner. You'll need a bunch of each...I'd start with a few hundred. Only one crate or chest is needed though. You'll also need several sets of tinker tools. Once you have your tinkering and remove trap skills at 58 and 50 respectively (or very close to that), you can begin training. Start by recording a macro that double clicks your tinker tools, then selects the dart trap from the traps menu, then targets the crate or chest in your backpack, then uses the remove trap skill, then targets the crate or chest again, and finally a 10 second delay. Then loop it. You could make this a little more complex with an if/then statement to try to retrap if setting the trap fails or remove again if the first removal fails, but what I have here works just fine. Here is what my macro looks like.
Once you have that macro set, run it until your remove trap skill sneaks up on your tinkering skill. Once it gets to within 4 points or so, stop the macro and then make lockpicks again to raise tinkering up to 8-10 points higher than remove trap. This and restocking your ingots, crossbow bolts, and tinker tools are the only reasons you have to keep an eye on this training macro. Don't worry about setting off the trap and hurting yourself with this method because even though you trap the box, you never actually arm it.
Once you have that macro set, run it until your remove trap skill sneaks up on your tinkering skill. Once it gets to within 4 points or so, stop the macro and then make lockpicks again to raise tinkering up to 8-10 points higher than remove trap. This and restocking your ingots, crossbow bolts, and tinker tools are the only reasons you have to keep an eye on this training macro. Don't worry about setting off the trap and hurting yourself with this method because even though you trap the box, you never actually arm it.