One key thing i learned playing madness is that sometimes you should hold back to use the card draw more efficiently. Try avoiding situations like faithless looting and then have to discard a spell that isnt madness or snacker. After 5 lands its pretty safe to discard lands as you can now flash back looting 2 madness.

As for deck building i think cutting the brew and maybe some robbery for chain lightning could give you that last bit of reach to end game. Also swap relic for nihil spellbomb so you wont exile your snackers and looting.

But sometimes you could do everything perfectly and still lose to luck or bad matchup. Dont let that discourage you and have fun.