The Conservative answer would be to learn teffelin (if you're Jewish, male or female) then worry about the the Red String.
That makes sense to me personally, because Tefilin is more of a religious thing - and thus outer, and red string is inner and spiritual.
Here the schools of thought vary - some say religious observance comes first and the spirituality stems from it; in my case it was the other way around.
BUT
its all unimportant - the only thing that matters is said by Hillel, an ancient sage (there are various versions of the legend, this is my favorite):
he was approached by a newbie student of Kabbalah, overwhelmed by the quantity of the information; the student said
-Teacher, please, tell me what i really need to know while i stand on one leg.
(Read - in shortest possible time!
)
The other students got enraged - like, "how can you expect to learn such wisdom in a short time, its impossible, you are rude and stupid too! "
But the wise teacher waived with his hand and said "Love your neighbor as yourself; all the rest is commentary."
ETA: i have non-Jewish friends wearing tefilin, it works anyway