These guides are written to best suit non-paying players and using NO limited set pieces or pieces the player is not able to obtain at their current level. It is made to be followed with the maiden & princess levels being done in tandem as soon as princess is unlocked. This is also focused on North American and European players. While players in other countries can use this be advided that some "standard" pieces go by different names in other countries or are not included.

Since the following sets are given to all players as of OCTOBER 2017 they are included in the sets. If they are ever not given out standard the set will be updated to reflect the changes. If you see an outfit that has pieces you can't find email me at love.nikki.guide@gmail.com so I can take a closer look at this for you.
  Youth Storm (after 10 minutes)
  Ice Blue Rose (after 24 hours)
  Bright Galaxy (after 7 days)
  Wonderful Holidays (after 10 days)
  Raspberry Pink Rock (after 21 days)
  Cinnabar Cloud (after 30 days)
  Pink Wishes (for connecting Facebook)
  Winter Angel (first diamond purchase)

In addition, I will do my best to avoid buying items that use diamonds. Since diamonds are earned through progression through the game, and doing the daily quests; I will purchase some diamond clothes, but nothing that should require you to buy diamonds. The game starts you off with around 500 diamonds and I recommend saving those for clothes or events.