Killer Instinct

I would do this at the same time as getting the related Survival Achievements. You will also unlock the related color achievement too if you have started at character rank 1.

So,

Go into Survival, and prioritize the following combos:
(Survival and Supreme Victories will rank up)
(these will rank up in Combo Hits, Autos, Combo Enders, Ragged Edge and Eclipse)
(Back, Forward + Punch), Punch, (Back, Forward + Punch), Punch, (Back, Forward + Punch), Punch, (Down, Up + Heavy Punch)
(Back, Forward + Kick, Light Kick), Punch, (Back, Forward + Punch), Punch, (Back, Forward + Punch), Punch, (Down, Up + Heavy Punch)
(the below one will rank up in Aerials, Manuals, and the same as above)
Jumping Punch, Punch, (Back, Forward + Punch), Punch, (Back, Forward + Punch), Punch, (Down, Up + Heavy Punch).

I would advise getting in as many throws

When the Opponent is in danger, prioritize the following combo:
(this will rank up Combo Hits, Autos, Ragged Edge, Eclipse, Shadow Moves, Ultras)
(Back, Forward + 2xPunch), Punch, Punch, (Back, Forward + 2xPunch), Punch, (Back, Forward + Punch), Punch, (Back, Forward + All Punches)

Advanced:
At the end of the Ultra Combo, hit Down, Up and 2xPunch and it will hit the opponent on the way down. During this attack, hit 3xPunch and 3xKick to perform a Combo Ender(In this case, his flip kick from KI Gold)

After 10 Survivial matches, if you don't have 30 fight challenges by then(It should pop no later than the 7th match), keep going.