If you don't want to use an extra auto-click program to help you do the first job there is a very old glitch to help you.
1. either click on the job skill to save it in the short-cut box on the right or assign a F1~F8 key
1a. if you clicked on the skill or are in the skill mode right-click to go back to normal state (peace mode)
2. left-click on the tree, water, stone, etc. you want to use your skill on and keep the button pressed (like auto-attacking/walking)
3. now while the left mouse button is still pressed activate the job skill via either your F-Key or the short-cut key (and keep the mouse button pressed...all the time)
4. enjoy auto-click for your jobbing
Now this isn't as useful anymore since you'll need to pickup items once in a while and won't get job exp by doing it for a long time but I still found it useful while getting my items so far since the failrate is so high and clicking all the time is very frustrating for me.
Also even though it's some kind of glitch it shouldn't be fixed imo, or if it gets fixed the auto click should also work for jobs by default without having to use this workaround.