Analyze your slower games, not your blitz games.
Don't continue playing all your games against players rated so far below you.
In rapid chess, almost all your opponents were rated 400 points below you. You have a rating of 999 You are 28/1/4 and your best win is against a 638 rated player.
That's ridiculous. Take your chances. Then you will have some games worth looking at.
Well he is 74-78 in blitz, rated 700 something. My guess is that he is probably under the misunderstanding that ratings should be the same in blitz and rapid, rather than trying to select easy opponents. For whatever reason, rapid ratings tend to be several hundred points higher here.
Anyway, at your rating level the major thing going on is that one keeps missing that the opponent can take pieces for free, and missing when you can do that to your opponent. This accounts for virtually all wins and losses at your level. Secondarily, you likely do not know and apply many of the basic beginner rules like develop (i.e. take out) your pieces (knights and bishops) and castle before moving your pawns a lot. As to the first problem, besides playing more slow games to practice a careful thought process, the other thing that helps is doing a lot of tactics problems. I see you have done 85 problems here, which isn't a bad start, but considering you have almost 200 blitz and rapid games, 85 isn't very many either. Chesstempo.com has unlimited problems for free members and just gives free members more of the kind of perks that they charge for here. As for the second problem, if you post a loss we can let you know some of the beginner rules you violated.
Cheers.
You were doing fine until you castled and left your queen unprotected.
Is there any reason to look further?
Bad tactical oversights and bad positional knowledge. A few tips to get you going:
(1) Watch out for bringing your knight out to the 3rd rank if it can be chased off by a pawn immediately (3...e4). Read or watch parts of "My System" on YouTube about this.
(2) Stop playing 1. c4. That's for pros who know all the many transpositions and many heuristics and lines that a novice cannot learn in any reasonable time. Just play the usual 1. e4 or 1. d4. In general you can consult a free online database to know which moves are the most popular, which are usually the best moves.
(3) Get a central pawn duo with d4 and e4 as soon as possible (2. d4 in this game), or at least d4 and c4. That should be one of your primary goals in the opening (e.g., 1. c4 Nf6 2. d4, or 1. d4 Nf6 2. c4).
(4) Watch for obvious tactics that involve captures, checks, or both: 14. Bxg6+, 18. O-O?? Qxe2.
(5) Castle earlier, usually before sending any pawns to the 5th rank or opening up your e-file.
10 e4 does not develop a piece, allow you to develop a piece, nor does it castle. Beginner rule is focus on developing and castling. It also looks visually immediately questionable to more advanced players given that his queen is on the same file as your king -- the pawn is pinned, and can't capture the fpawn for example.
You missed many tactics including some not mentioned such as 16. d6! That is kind of an advanced one for your level, but if you did not see it, then 15. d5 violates the beginner rule - develop + castle before you are spending time pushing pawns for no clear reason.
[Site "Chess.com iPhone"]
[Date "08/13/2017 10:01"]
[White "MrDoga (697)"]
[Black "fdtygtgtfdy (666)"]
1.c4 e5 2.Nc3 Qh4 3.Nf3 Qf4 4.g3 Qg4 5.Bg2 Bb4 6.Nxe5 Qd4 7.Nf3 Qd6 8.a3 Bxc3 9.bxc3 Qa6 10.d3 Qxa3 11.Bxa3 d5 12.cxd5 Bf5 13.Nh4 Bxd3 14.exd3 Nh6 15.Qe2 Kd8 16.Qe7 Kc8 17.d6 Nd7 18.Bxb7 Kxb7 19.Qxd7 Rac8 20.Rb1 Ka8 21.Qc6# {White Wins}