Hi Oman! Nice to meet you. Its good that you want to be good in a year. I have 1 year playing melee so I can give you some tips that helped me.
1) Select a main and play with it everyday. I know that someone wants to main 2 or 3 characters but its easier to dedicate your time to one character. First get very good with 1 character and then, try anothers for tournaments.
2) Try to play at least 15-20min everyday but wisely. Learn how you character moves, what works, what dont, learn combos, and different ledge options. Looking at videos also help.
There are some YouTube videos from Armada where he talks how to be good at smash and character selection, and they were very helpful when I started to play smash competitively and when I got frustrated sometimes.
Hope I've helped you with these tips!
Have a good day(: