Note: As of July 2017, people have reported this achievement not reliably unlocking upon completing all challenges. Based on previous experiences with MS Casual Daily Challenge achievements, I'd recommend repeating a challenge after completing the month to try triggering the achievement.
Some tips and guidance for conquering the daily challenges:Gem Collector
The challenge is random every time you start it. It is possible for the presented challenge to be unsolvable (like if you have a highlighted consonant in a corner surrounded by other consonants that don't get along with it). Clicking the restart button in the upper right is helpful to reset the board in this situation, or if the challenge has a whacky tile that the solver you are using can't handle.
The solver I prefer to use is: http://www.dcode.fr/wordament-solverBomb Defusal
Another random every time you start it challenge, although you won't come across unsolvable challenges.
The solver I prefer to use is: http://www.wordfind.com/
- I've yet to encounter a challenge word it didn't know about, and there's a very low rate of words it gives that the game doesn't accept.Mystery Clue
These will be the bane of your completion quest, as they take quite a bit longer to solve then the other two challenges. Fortunately they are only partially random: the crossword itself will be the same every time you start it, but the mystery clue itself will be random each time. I highly recommend screen-shotting or otherwise writing down the crossword solution before using up your last mystery clue guess. Don't repeat my mistake of having to completely redo an Expert challenge just from memory after blowing the one and only chance presented.
There are so many crossword solvers out there, and they all have varying levels of success helping with these challenges - I've yet to find a preferred one. I will say the mystery clues that I can't figure out on my own tend to stump the solvers as well.