Leveling a job from 1-10 in a day can be grueling if you are just learning to play the game. For players that have jobs in the upper lvls it is a bit easier because skills are already built up that give you a bit of an edge. Also the knowledge that you've gained by actually playing helps also.
But all in all if you play it safe, it might take you a while but you can do it in one day. I personally am in the slow but steady wins the race camp of thinking. I don't go for Toughs and only on rare occasions and with certain jobs will I do Even Matchs. The time wasted respawning, running back to your spot, and getting back into the swing just aren't worth it, imo. Even though exp loss is minimal post lvl 5, it's still a minor setback and not worth it either. Now my son is the type that just goes out there and wants it done as fast as possible. We did a little test after many arguements over who's way of thinking was better. We leveled 2 jobs (same ones) from 1-10 on a brand new character. Both times, I got to 10 before he did. It wasn't by leaps and bounds but I made my point.....doing it his way was not faster.
Some tips:
1) Know what mobs drop and check the prices before you go out. This way you know what isn't worth keeping to sell and can toss it. The less trips back to town to empty your inventory the better.
2) USE FOOD! If you are a mage, mp+ or mp regen foods will keep you on your feet longer which means more expz. Attack food helps you kill faster which also means more exp in the long run. Some people swear by hp regen food for melee/tank when you are soloing in the lower lvls, I think its pretty much the same either way.
3) If you can afford a weapon OR armor, get the weapon. 1-10 really doesn't have any MUST HAVE armor but without a good weapon it will take you a lot longer to lvl.
4) Do some research on the mobs in the area you are going to fight so you know what to avoid. What aggros? What links? What are some of the moves they do that can **** you up? (Watching your hp tick down because you are poisoned/bio'd sucks horse hockey!) Do this while you are finding out what the mobs drop so its pretty painless.
I'm sure there are lots more great suggestions but its late and time for me to get my boney old butt in bed. How about it, what do you all suggest from your experiences?