everyday you get a daily apexis mission in your townhall garison this will reward 800-1000 apexis depending on the mission you choose
but the guy outside the townhall by the garison ressources sells those missions also i discovered that if i took the one in the townhall acept it then go buy the coresponding one from the vendor i could accept it also
and do both at the same time so 800 +800 = 1600 apexis daily i think this works because the name of the mission is slightly different
so far i was able to do this with the botani one and the one if frostfire ridge be sure to buy the right mission from the vendor
good luck have fun