As agreed, I'm posting you the sentencens I'm still not sure of.

Question

Thank you in advance

1) I spent my Christmas holidays chatting with my friends on my computer and playing songs on my guitar. I also played on my Nintendo-DS and I went to volleyball training (?) twice a week. I usually stayed up till late watching TV. I spent the rest of my holidays doing my homework because I had fallen behind
2) The following day we went to the seaside to my grandparents’ house. (or and stayed at my grandparents’ house). We played cards and I won all the games. I’m always lucky at playing cards!
3) On Christmas Eve I unwrapped the presents lying under the Christmas tree. I received a computer from my parents OR my parents gave me a computer as a Christmas present? Can I say I received a lot of presents such as …
4) During Christmas holidays (and not IN) I went (and not I went out) to a friend’s house. There were twenty-five people there. (and not we were …) We toasted to the New Year with sparkling wine, then we set off some fireworks in the garden and burst some crackers.
5) My aunt gave us for starter melon with ham, then pasta with tomato sauce and for main course chicken breast with chips.
6) On the Epiphany I went to the mountains and my mother drove us there (and Not by my mother’s car?).

Answer 1

Good for you!!

1) I spent my Christmas holidays chatting with my friends on my computer and playing songs on my guitar. I also played on my Nintendo-DS<~~add comma and I went to volleyball practice twice a week. I usually stayed up (delete "till") late watching TV. I spent the rest of my holidays doing my<~~delete "my" homework because I had fallen behind<~~add period

2) The following day<~~add comma we went to the seaside to my grandparents’ house. We played cards<~~add comma and I won all the games. I’m always lucky at playing cards!

3) On Christmas Eve<~~add comma I unwrapped the presents lying under the Christmas tree. My parents gave me a computer as a Christmas present, and I also received a lot of presents such as …
(Yes, this sounds good.)

4) During Christmas holidays<~~add comma I went to a friend’s house.<~~all is correct! There were twenty-five people there. We toasted to the New Year with sparkling wine,<~~semicolon needed here, not a comma then we set off some fireworks in the garden, as well as some firecrackers.

5) For starters, my aunt gave us melon with ham, then pasta with tomato sauce<~~add comma and for the main course<~~add comma chicken breast with chips.

6) On the<~~delete "the" Epiphany<~~add comma my mother drove us to the mountains.