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at OTB, it is good manner, against expert or master, to resign such game as gentleman. you may always analyse further after the game ended...
I heard of a time (pre-stockfish) when an expert had a lost position against an IM and offered an immediate resignation in exchange for an analysis session afterwards.
if you want to make progress in real chess (not online blitzing and bulleting) you should analyse your moves and mistakes first instead playing completely lost game and hoping your opponent would drop both rooks, queen etc...
self critics should be at first place, not oportunistic appproach.
at OTB, it is good manner, against expert or master, to resign such game as gentleman. you may always analyse further after the game ended.
how to convert and checkmate when you are queen up or whatever.... think every beginner should always start with basic endgames, at least this is what old masters back in 90s used to advise us. later on you go to more complex positions step by step.
why engames? because every position, when you have extra material is normally reduced till the endgame, You don't go for crazy checkmate combinations as priority when you are piece,or three pawns up, or rook up. You first stabilise your own position and start to reduce material gradually... systemathically pushing your opponent into lost endgame.