Defeat!!

Can someone tell me why I am losing so easily its been 1 month I am still at 800 elo.
Even after watching so many opening and other things I cannot gain in a day i play around 10 to 20 matches I only win 1 and loses other for this i play on lichess as a guest but I still lose I just like resign most of time when I watch any opening like vinnea game and Ruy Lopez I can't practice there never come any situation on which I can use that opening and traps.