Hey man, I'm a 1s main and I recently just hit Champion 1, so I might be able to help. From what I've seen and experienced, graduating from Platinum is all about consistency. Rather than experimenting with aerials as offensive techniques, focus on using them defensively and at close range, such as a slow but high bounce towards your net. Make sure your ground play is solid and you can dribble and occasionally flick. Typically when you're in the air, you're leaving the entire field open making it very easy for the opponent to score. At your rank, it's far more advantageous to wait for your opponent to make a mistake, rather than forcing a risky play and making a mistake yourself. When defending, try and think of what shot you would go for and what position would be best for defending that. Over time, you'll develop as a player, and positioning yourself will become more and more natural. Hope this helps!