For you creatures I'd suggest making them a little more focused. Keeping your creatures to one or two types can benefit you greatly and will allow the use of lords (creatures that give +1/+1 to others of the chosen creature type, for example
Knight Exemplar for Knights) From here you can find creatures that benefits from the lords' effect as well as its own. I notice your deck has alot of protection so to build on this example I'll use that too by bringing in both
Fiendslayer Paladin and
Mirran Crusader who both benefit from being knights whilst still carrying their own protection effects. ( I made a knight tribal deck a while ago which you can find here (
https://deckstats.net/decks/14650/96294-defenders-of-justice) if your interested.
For your other spells you seem to have a theme of lifegain going on which is nice but right now it doesn't really accomplish much. Yes it does help you stall for a while but ask yourself would you be better off casting something else or at the very least make it work toward a win condition by using something like
Chalice of Life,
Ajani Goldmane or
Ajani, Caller of the Pride.
I'm glad to see you using cards like
Path to Exile and
Disenchant as focused removal like these are usually pretty good.
Oblivion Ring is another great removal spell in white and has the benefit of hitting anything.
Lastly I feel like the deck runs too many land considering nearly all of your cards cost 3 or less to cast. I'd say 18-20 would probably do this deck in its current state. Since your also running mono color
Nykthos, Shrine to Nyx would be great for mana ramp. Other devotion cards may also be useful to you but that's up to yourself.
Hope this helps:p