Hello can you give me some advice for handball goalkeeper?

Hello can you give me some advice for handball goalkeeper i have 17 years old and i am working so hard and i am second goalkeeper in the team give me some advice what to work and how to work because coach it is not so interesting with goalkeepers. Thank you

Depends on what you are good at and what not so. Analyse your playing style and come up with some things you must improve. Only then I can give you some advice on what and how to train.

Meanwhile try to convince your coach that a goalkeeper is his last defender and his first attacker. That a goalkeeper can be of great importance in winning or losing matches.

Perhaps you should try to convince him to train with drills that involve a lot of goalkeeping, so that you are always involved in the game, so that you can improve during attacking and defending drills for the team when they shoot at the goal.
Ask him to give the players certain tasks when shooting at the goal : only top corners, only bouncing balls, only low shots, so that you can improve your goalkeeping qualities.

Hope this can help.