I uaually use the karnak escape to stock up on elixers. You can easily gain over 20 in there alone.

Side quests are in short supply at this stage in the game. You probabley have shiva and ramuh by now and you probabley visited tycoon castle already, i think thats pretty much all there is to do. You'll get more and better side quests later.

For AB you can do as rubah suggested. Skull eaters might not appear as often as you like but the only other place i can think of where AB comem in moderate supply is the area surrounding the forest where ramuh is found. You get between 3 and 5AB for killing the enemies there.

What you could do is try to learn all the available Blue magic.