I Need Advice

I just competed in my first chess tournament this year. I went 2-3-1. I was in the middle; not trash but not crazy good. I want some advice from higher rated players on the following things:
1. When I’m black I tend to struggle playing offense. The last game I played someone solid and I found myself playing defense the entire time. I want some things for black that allow me to play offense and attack pieces rather than defending their offense the whole time.
2. What is the best way to defend both the queens pawn opening and the queens gambit? I saw the queens pawn every time I was black (four times). I played d5 in response. They never ran the queens gambit, instead they would get a knight or bishop out or something. I think I got one of my knights out and went from there. Any ideas on a different way to defend queens pawn? Then for queens gambit. I didn’t see that but I am curious. How would I defend that? I don’t like to accept, but I don’t know the best way to decline.
3. I struggled with king protection in my first game, and it cost me the game in 20 moves. Any advice on that? I like to castle the short side.
4. If I play an opponent that is just better than me and I know that going in, what’s the best way to play my best game? Do I try to throw everything but the kitchen sink at them or do I just do my normal stuff?

If you could answer those questions for me that would help me out a ton. Thanks!

was the tournament Over The Board or online

and if it was otb what is your rating

It was over the board. It was a school competition. Your rating doesn’t really matter because if you win you play winners and if you lose you play losers. It all depends on how you’ve done at the specific tournament, not other tournaments.

I hope that helps

for number 2 you should look at an opening lesson on either the queens gambit declined, the nimzo-indian defense, or some other queens gambit opening by going to learn on the side and going to openings.

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Opening suggestions (in my opinion): 
"When I’m black I tend to struggle playing offense. The last game I played someone solid and I found myself playing defense the entire time. I want some things for black that allow me to play offense and attack pieces rather than defending their offense the whole time." - Sicilian defence/Scandivanian defence/Caro Kann defence 
 
"What is the best way to defend both the queens pawn opening and the queens gambit? I saw the queens pawn every time I was black (four times). I played d5 in response. They never ran the queens gambit, instead they would get a knight or bishop out or something. I think I got one of my knights out and went from there. Any ideas on a different way to defend queens pawn? Then for queens gambit. I didn’t see that but I am curious. How would I defend that? I don’t like to accept, but I don’t know the best way to decline." - Queens gambit declined, cambridge springs defence
 
" I struggled with king protection in my first game, and it cost me the game in 20 moves. Any advice on that? I like to castle the short side." - Castle as early as possible and not be too committal in the opening
 
"If I play an opponent that is just better than me and I know that going in, what’s the best way to play my best game? Do I try to throw everything but the kitchen sink at them or do I just do my normal stuff?" - Play your normal stuff
(chess.com, please render \n)

Sicilian cannot be played if d4 is played, as was said

Chessbit64 if you have advice type it in here

I based it on a case-by-case analysis, d4 was not mentioned in the first statement

If you guys are trolling please stop

ok

Those are difficult questions and in some respects there might be no such thing as a reliably good answer. White has the first move. Black is always more likely to spend time on the defensive from the opening, and various zappy-trappy Black gambits tend to end sadly if White plays well and doesn't fall into a trap. You might find that you need to work on your defensive play to prosper (I don't think there's ever been an Algebraic edition so you'd have to deal with the old Descriptive Notation, but Keres and Kotov's The Art of the Middlegame" has a very useful chapter about playing on the defensive). I'll do my best here, but there's no "magic formula"...

1. and 2. Have you got your head round the Hypermodern openings? The idea is to treat chess as a "game of information" and use the moves White has already made against him/her. Almost guerilla warfare against a central edifice with pinpoint strikes against wherever looks weakest.

1...,g6 or 1...,b6 against everything (within reason - 1. g3, b6 is of course dreadful for Black) is fairly easy to learn, for example there's a rather good Lakdawala book on 1...,b6.

Hypermodern isn't for everyone, but does have the advantage for Black of not just spending the opening just trying to smother what White is up to - Black gets to scheme his/her own schemes like a Sumo wrestler sidestepping his opponent's charge and using his momentum against him.

3. Is rather vague. I can't be concrete. Analyse your specific defeats.

4. I swear by a recommendation in another rather old book: Simon Webb's "Chess for Tigers". He recommends going for unbalanced complexity against way better players (and quiet technique against lower-graded ones) on the basis that the messier the position becomes the more likely anyone is to miss something.

Hi there.

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Take a look at the Tarrasch Defense striking at the center a bit too soon with 3...c5 (instead of the principled main move 3...Nf6): 1 d4 d5 2 c4 e6 3 Nc3, or 3 Nf3, c5) against the Queen's Gambit and see what you think. It's what I play. I use the repertoire book titled Fight 1 d4 with the Tarrasch. It's a good book but is 380 pages loaded with lines, a bit much for me so it might be overwhelming to you just yet. The book The Tarrasch Defense by Sam Collins is also good and may be better suited for you at this point. It's 250 pages, not loaded as heavy in lines as the first book I named, plus Collins' book has a Tarrasch Defense pawns structures chapter that could be helpful. In the Tarrasch Defense Black is willing to take on having an isolated queen's pawn for more freedom.

Note: Not to be confused with the Tarrasch that white can play against the French Defense (1 e4 e6 2 d4 d5 3 Nd2).

Against 1 e4 once again on purpose I strike at the center a bit too soon in a bid for more room, the Scandinavian defense, 1 e4 d5. There are 4 main versions of the Scandinavian: 2 exd5 Nf6 or 2 exd5 Qxd5 3 Nc3 ---3...Qa5, 3...Qd6, 3...Qd8. I've played them all and I prefer 3...Qa5. For 3...Qa5 I use the good repertoire book The Scandinavian for Club Players. The author not only provides a repertoire, he teaches about it. The book also covers when white varies early after 1 e4 d5 with moves such as 2 Nc3, 2 e5, 2 d4, and when white plays 3 Nf3.

They are not considered top tier defenses. In the Tarrasch Defense black is willing to take on having the IQP weakness. In the Scandinavian black is willing to have the queen come out too soon. Pros and cons.

Black isn't actually attacking in those defenses though if that is something you are requiring. Black can hardly attack right out of the opening.

The Modern defense 1...g6 is usually played with sharp counterattacking striking intentions but it is difficult to play well, black can get crushed if not played accurately. World class GM Nakamura uses 1...g6 a lot in his blitz and bullet games and does well with it, but he's Nakamura.

The rating does matter if the pairings are made using the swiss tournament rules