Okay, if you need help, it would be very useful if you write some words in the description or in the forum about the deck.
What also helps me alot is putting the cards in custom groups by function. Lands, draw, ramp, recursion etc. Already the grouping itself sometimes points outs weakspots (e.g. you notice that you've added only 1 card for additional card draw). Besides that, its way easier to understand the intention by adding this or that card and it's sometimes easier to see some synergies.
If you want to read some stuff about brewing (and cutting) commander decks, I'll reccomend this topic:
https://deckstats.net/forum/index.php/topic,42562.0.htmlAbout the wincon, if I'll take a short look on your current deck, I'm not sure what you're trying to build, except trying to abuse the second part of your commander. In general I think you can build Sevinne in 2 ways: Spellslinger or voltron.
If you go spellslinger,
Devil's Play might interest you, since it would allow you to kill 2 players with one card (if you have the mana). combos for endless mana/spells would be useful. The easiest here would be
Dramatic Reversal +
Isochron Scepter. With that, there are sereval ways to win:
Grapeshot,
Aetherflux Reservoir, etc.
If you want to go Voltron, you would have to make bigger changes to the deck, but since sevinne can't be damaged, it's interesting, since your opponent's blockers doesn't matter most of the time. Besides that
Pariah and Shield of
Pariah would also make you invulnerable as long as your commander is on the field.