此 is often used with a classifier： for example: 此次旅行，此次会议 Of course it can also be used just before a noun, but generally it is used in writing, news report or some popups like "此项服务不能使用"（The service is not available）, something formal. 这 is used everywhere, more oral

Habit words,According to the context used. t thingk about " good moning " and "moning"

“此” is a written language expression, while "这" is included to a colloquial kind. Besides, “此” is adjective possessive pronoun, and “这” is nominal possessive pronouns. When it comes to "这", there will be a quantifier follows it in the most cases, for example,这个/这条/这座... Do u get it？ ^ ^ !

此 mostly means 'now' and 'here'.

I think it's also worth noting that 此 comes from classical or formal Chinese.