Its a riddle… and because we hear it so often we complicate the issue! 
Did the chicken come first, or the egg?Did the chicken insist the egg came first? Or was it the egg that gave way to the chicken?
The egg… because of evolutionary theory, we believe. Cold-blooded egg-laying animals were first, and one of these will have eventually evolved an egg to hatch a bird that laid the egg that hatched the first chicken.
Now, often place the same complexity into our conundrum with successful action or successful planning. 
The truth is, we can not survive without some thought, and some action. Neither are mutually exclusive. And action (successful or not) leads to better planning.
Yes, yes… you may say, “but what about the lucky”. I say you cannot be that lucky for long enough to sustain a full life. Conversely, if  you perform the right actions long enough, you will achieve success*.
It follows:
+ thought + no action = failure.
+ action + no thought = failure (except for luck, which is at best unreliable).
So, it is not “you first” or “me first”, says thought and deed. Rather it is “us together”. 
Now, go forth and do! In your doing you will be, and so will we. 
How you define success is personal, but only happens in and because of the community around you. #GiversGain, if you will.