PL Vs MS Dollars How Do You Tell?

Hello,

Despite 40+ years collecting coins, I am not a good grader.

I often cannot tell a flashy premium MS58 from a solid 65.

Anyone got any sure fire suggestions how to tell proof-like Canadian silver dollars from premium MS examples, especially from the early 1950s? Most especially, how do you tell a 1953 PL dollar from a premium MS example of that year. I've had some people tell me that in 1953 what are generally called PLs are just the upper end BUs.

Would appreciate any help in learning to spot PLs of that period.

Thanks,

Steve