In game.
Falco is a character that rewards patience, that is easy to forget when you think of the crazy pressure and combos everyone loves, but it's true. Wait / DD between lasers, see if your opponent commits to anything, space bairs when he's in the corner, dair in place when you think he's about to rush in etc.
The other thing you should value above everything else is center stage. When you have the stage, you have lasers, and you have patience, Falco is the boss. Every exchange is heavily in your favor : his ground movement is limited by lasers AND the corner, you have great zoning moves (utilt, ftilt, jab, bair, even nair/dair) and your godlike jumps let you hunt him wherever he jumps to.
So this is true vs fox falcon etc. And it is CRITICAL vs sheik marth peach etc. You forget about it = you lose, basically.
Not losing in tournament is nice generally, so I recommend you write it down, keep it in mind at all times when you're warming up in free play. Make this part of your identity. Get good at getting out of the corner and capitalize whenever you get center stage. And again : Patience = W.
Out.
I won't write about how to improve right now. This here is good stuff
http://alexspuffstuff.blogspot.fr/p/improved-drastic-improvement.html
Play better players, training routine, define objectives, analyse sets, write **** down etc.
I haven't read much on mentality specifically in tournament, but I would very much like to.
Diet.
Tested and approved :
- DO NOT eat junk food. Digesting fat and transformed food actually requires a lot of energy. You can feel heavy, your mind can be clouded or easily distracted.
What you need
-proteins. Ham, cold chicken
-vegetables so you're full but they're still light on your stomach. I like tomatoes, cucumber, paprika, carots
-fruits. vitamins and sugar, they energize you and boost your focus. Apples are top tier : easy to pack, nourishing
-snacks. twix kit-kat chocolate bars. you don't want to run out of availible sugar between meals.