It doesn't matter entirely on how many hours you put in SSBU. What matters is the quality of your performance.
1. Change your attitude.
A demoralized mindset or a mindset that leads you to believe you're a failure will hinder you. You've already lost against yourself. Accept defeat and try again. Learn from your mistakes. Consider every opponent you encounter as a potential threat, otherwise you might go easy and lose as a result. However, don't let this be a stressor. Simply understand that it's better to get a feel for who you're dealing with.
2. Focus on using proper strategies and tools.
What if you use a smash attack against your opponent who is barely at 30%? That would be a bad idea because your opponent isn't even close to killing. Use attacks that are quick and effective. Need a ranged, safe attack? Go for a forward tilt. Is your opponent too close? Try a grab or jab. Is your opponent far? Move in and try staying in the center of the stage. This gives you stage control. Is your opponent recovering low? Try a down aerial or perhaps a neutral special to send some ice downward. (You use Ice Climbers from the looks of it.)
3. Observe your opponent.
If you keep looking at your own character, you're going to miss seeing what your opponent is up to. If you're not confident looking at your opponent while playing, learn to develop a sense of your surroundings, as well as the direction you're facing without looking at your own character. Think of this like typing on a keyboard. Sure, you could look at the keys, but typing without looking at them is much faster and more effective. You should watch your opponent at all times. How many jumps has your opponent used? If your opponent was hit or thrown off-stage, he or she only has one jump (except for characters with extra mid-air jumps) and an up special (unless you're Jigglypuff).
Every time your opponent is hit or thrown in the air, more often than not, he or she will only have one mid-air jump. If he or she uses that, you'll better succeed at hitting him or her. Also observe how your opponent returns from the ledge. In SSBU, getting up onto the stage isn't safe like it was in previous games. Rolling, jumping, or using a get-up attack are the better options. Does your opponent always roll up? Watch where he or she rolls and where that roll ends. Stand at that distance or wait for your opponent to roll and go for the attack. Does your opponent always use a get-up attack? Shield the attack. Does he or she always jump? Try using a neutral air or an aerial attack that has good range.
4. Have fun.
Have fun. That's all.
