DachessJoker vs johannw
3...Nc6 is not usual, but not bad. It's like a Chigorin QGD except black goes 1. d4 d5 2. c4 Nc6 3. Nf3 e6!? instead of the usual 3...Bg4. The normal move in your move sequence would be 1. d4 d5 2. c4 e6 3. Nf3 Nf6, keeping your c-pawn free to challenge the centre.
9...Qd6 is playable since 10. c5 removed some pressure off your centre. However, 10...Qe7 would have been a better response, preparing a quick ...e5 to fight back in the centre. Anyway at that point, you need to castle, get the bishop in the game, and likely relocate the c6-knight that's doing nothing.
Moves 11 onwards: Castling quickly would be nice. ...0-0 could be played at almost every stage.
16...cxb5?! Why? Just castle. This move weakens your pawns.
17...b6? WHY? This gives white a protected passed pawn with tempo, and you still haven't castled while white's fully developed and ready to blow you away on the queenside.
19...e5 was an interesting idea, but probably 19...0-0 was better, followed by ...f6 preparing ...e5. The thing is, white's 21. Nd4? was not forced (21. Ra4 is very good) and so your move actually lost a pawn.
25. c7? was bad; 25. Rxa7 would have killed your queenside on the spot. You lucked out here with white giving free gifts.
The draw was agreed a little too early. It's better to gain experience by playing it out, especially endgames, which are important to improvement.