Something I noticed was that the opponent keeper will very briefly turn their back to the action, which is a good time to shoot. But the timing has to be perfect before they turn back again.
When I play the first 3 YYB games every day, I will start over as many times as it takes for me to get 7 goals so I can earn 3k NP. If I don't score those 7 within a certain timeframe or get too many Darigans, I'll restart.
Another thing I'll do is commit "sui***e" when I get a Darigan. I'll grab the ball, go to Xana and give it to her, then make her score an own goal. Yes, the opposing team gets the goal, but it means I don't have to waste time trying to score myself. However, I'll only do this if I'm a good bit ahead in goals, or if there's plenty of time for me to score more.