Should not take the pawn on C5 with king in endgame....

0:04 - Develop your pieces. Don't make pawns moves in the opening if you can avoid it. 0:11 - Don't play h3, develop bishop or knight or castle. This is a basic opening principle. 0:15 - g4 wins a piece. Always look for aggressive moves first so you don't miss tactics 0:26 - Qd2 is not best. Keep developing with Nd2. Avoid making early queen moves. 0:33 - Nf3 wins. Missed tactic. The rook is pinned 1:31 - If you are the winning side, do not exchange pawns in the endgame. 1:32 - Stop opponent's counter play first. Ask yourself ways your opponent can draw or even win. Be patient and stop him. Patience is key in the endgame