Breeding is a pretty good way to get a shiny, but, if you don't want to breed, there are other options.
SANDWICH HUNTING
Using Herba Mystica (obtained from 6-star Tera Raids) in combination with other sandwich ingredients can make a sandwich with these effects:
Sparkling Power (Type of your choice): Lv. 3
Title Power (Type of your choice): Lv. 3
Encounter Power (Type of your choice): Lv. 3
Sparkling Power increases shiny odds to about 1 in 1024 (without Shiny Charm).
Title Power is just an added bonus; it increases the chances of having a rare "title", shown when a Pokemon enters a battle.
Encounter Power drastically increase the chances of encountering a Pokemon of that specific type in the wild.
To use this method, find a place where your desired Pokemon spawns and is about the only Pokemon of that type around. Then, make your sandwich and you should be seeing loads of that Pokemon and (hopefully ^^) a shiny.
This chart is a guide on how to get the sandwich right for your type of choice.
This is the main way to hunt shinies in S/V, and, if you dont want to breed, this is likely the best way for you.
For an added bonus, if there is an outbreak of your desired Pokemon, K.O'ing 60 of them increases your shiny odds (Credit to CharlotteMillton in the comments).
Hope I helped!