Size of spoons?

They're all good.  Sizes and colors.  Some don't work some days, all work others.   A fresh-from-the-trenches chromer won't be afraid to nail a 3" spoon, in any color.  Other times, 1 1/2" plain silver spoons will be the ticket.  Not to be too big a jerk, but give it all a try newbie, you just might learn yourself something.

I try to stick to 1/8 ounce Cleos and the smaller sizes of Krocodiles and Kastmasters.   This greatly minimizes hanging up on the bottom.  The larger ones are fine, but expect to lose some to the rocks.  My 1/8 ouncers were quite effective yesterday in front of one of the streams.   Blue/white glow in the dark was good until full daylight, then blue/silver, green/silver worked well until the lake stirred up.  I landed 5 from 5-9# and my dad landed 3 of similar size. 
Also, the smaller sizes tend to work better as the water gets colder (if it gets colder this year).  They are effective until the water temps get down to 52 or lower.   Then I switch to various baits and smaller sizing. 

Spoons do work, but some people misuse them.  I have seen guys purposely throw out a big spoon with large trebile hooks and snag fish.  Then they act surpised that they "hooked up", like they weren't really trying to do it. If u cast one of those things into a tightly stacked group of steelhead, you're gonna snag one eventually.  So if you use a spoon with trebile hook, just be careful.