Using real time is not required for any category, but I recommend using it for very long runs.

Any% - Reach and finish 6-14 as quickly as possible. You can use any levels within the first 5 areas in order to get there. There are Star requirements for each world, with 10 starting out in the first world and 58 required to unlock Area 6. Clean save file required.

All Time Trials - Play all levels marked green and orange on the Stage Select screen, with 6-14 being the last stage. You do not have to fight any bosses. Clean save file required.

100% - Play through all stages in Adventure Mode, collecting all the stars in the process. This includes beating every stage on Pro difficulty, getting all requirements in Boss fights, and unlocking/completely beating the final boss for 228 Stars. Clean save file required.

--MISC--

All Levels Normal/Hard - Play through everything on Normal/Hard difficulty, with the exception of the final boss. You may use your existing save file for this. An easier alternative for 100%, but keep in mind you may lose stars, so back up your saves just in case.

Area 6% - Unlock and beat all Area 6 levels quickly, up until Area 6-14. You can use any levels within the first 5 areas in order to unlock Area 6. You may also use any difficulty levels needed to beat those levels. Clean save file required.

Boss Rush - Play through all the bosses. Any% and 100% function as above -- clear as quickly as possible or go for the maximum star count. You may use your existing save for this.