How should a low rated player learn to avoid traps?
It just comes from practice and experience really. Watching videos and such helps because then we may learn about a trap and not fall for it (even if we don't play it ourselves), but more often than not: we will avoid traps because we have fallen prey to them before. It is simply part of learning. 
Keep following opening principles and keep trying to learn chess and that is all everyone does (even GMs are learning), but even GMs fall for traps sometimes. I remember an OTB game (USCF rated I think, but it may have been unrated) and I won against a player circa 200 points higher than me (I was about 1700 and they were about 1900 at the time). What was cool was that I played a line I knew well (I was Black) but I fell into an opening trap! I took the material loss from the opening trap, created complications and still was able to weasel a win out of a Rook endgame lol. I might have the game written somewhere, but getting it would be another story with all of my papers everywhere. 
If you don't want to get "out-booked", use something offbeat in terms of the openings. The Sicilian, Ruy Lopez, Queen's Gambit Declined, and King's Gambit are full of well-studied trap lines, both for white and black.
Other openings like the Reti & the Vienna for white, and the Nimzowitsch, Grunfeld, and Indian Defenses for black, are not as well-studied, but quite sound and easily played with a strong foundation in opening principles. Even Petroff's Defense, which has a lot of deep theory but is poorly studied at the low/mid-levels, can be played with success. If you know the opening better, then your opponent will have to worry about traps, you'll be spending your time learning how to set them instead.
fall into the trap once just dont do it again. do you have an example of an actual trap or are you just hanging material to your opponent. I find it a bit hard to believe players at your rating level are playing traps without you actually being lower rated than they are so as to lose to them. Btw WATCHING VIDEOS DOESNT MAKE YOU A BETTER CHESS PLAYER ANY MORE THAN TURNING ON A TV WILL MAKE YOU A BETTER ACTOR.
1. Players around 1100 do use opening traps. I started (using traps) at 1200, not too far off. I know, people under 1300 know openings (incredible). "I find it a bit hard to believe players at your rating level are playing traps without you actually being lower rated than they are so as to lose to them". Not sure what you meant, but I think I answered it.
2. Watching videos helps, unless you have literally no recollection of what happened. For example, if all you remembered from 10 videos was "Don't move your queen out in the opening", something you were doing a lot, and you didn't move your queen in the opening anymore... Then it made you a better player!
Honestly... you just have to remember them. But they usually have a common tactical theme to them, so it will be easier to remember. Take a look at a simple Evans Gambit Trap (black helpfully kills himself):
White sets up the trap with castling... I used it many times myself (and won all those games ).
Here is another common tactic, the opening is Alekhine's defense.
I looked over some of your losses, and it doesn't seem like you are following many opening principles, and I know that there are tons of exceptions. Many of the losses were due to you keeping your king in the center and not castling, or bringing your queen out early and getting it pushed around. With your game vs marijan99, you did castle, but you played 6. Qb6, which invites white to develop with tempo with Be3. Instead, I might have played something like 6. Bc7, playing for d5 with stuff like h6, Be6, and Nbd7.
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There are traps and there are simple traps. Most of the simple traps are easily detectable. Developing into a harmonious piece and pawn setup is the goal in the opening, but the same can be said at every stage of the game, with the difference that the material isn't in its initial square. So, play the opening concretely, paying attention to the problems you're trying to create and those you need to solve and leave the principles for situations where there's nothing to solve.
Now, simple traps are often the result of unprotected or lightly protected material, and the typical method is a double attack. So, whenever you have something that is hanging (like a black bishop in c5), you should also be paying attention to other material that is also unprotected or under pressure, as the rival may combine both ideas into a motif. For example, White with Bc4 and Qd1, Black with Bc5, Pf7, Ke8: The f7-pawn is protected, but the hanging black bishop creates themes for a double attack with 1.Qd1-h5, 1,Qd1-d5, and even 1.Bc4xf7+ Ke8xf7 2.Qd1-d5+ (or 2.Qd1-h5+) K-any 3.Qd5xc5. Now, should Black have a queen in d8 then he could defend against 1.Qd1-h5 and 1,Qd1-d5 with 1...Qd8-e7 (protecting both f7 and c5), but not against the line after 1.Bc4xf7+. So, besides the hanging and lightly protected material, you should also pay attention to your king being deprived of coverage and possible tempo-free checks which may pick something.
Of course, there are other motifs besides the double attacks in the opening, but they aren't as common, and you asked for a quick fix. Now, this is important: You may have noticed that most masters don't leave unprotected material. It's not that they have foreseen each line, but that they often "smell the danger", as an attack against that material may win a tempo or even tempos, even leading into a forced line. So, to avoid traps, you should learn not to allow free tempos to the opponent.
@nictator65 it would be better to use a board image to describe what you're saying, like this:
learn by playing. find your best move. then before you play it. find your opponents best reply.
@snudoo Maybe, although I'm of the idea that it's better not to use the car when I can get there in a 5 minutes walk. Chess wise, learning and training the mental images of pieces moving on the board is a big part of the answer to "How should a low rated player learn to avoid traps?"
