Stop thinking so hard. It will make
microscope work less boring. You won't get these right away (I've worked with vets of 20 years + experience who still can't use a
microscope) but if your hearts in it and you make it enjoyable and you'll learn faster (or maybe I'm just seriously disturbed). I think your main issue is appreciating relative size - which is bigger that which. Urates are a good reference size, as are bacteria. Collect a tiny scoop of just urates and have a look at them on their own - get an appreciation of what something looks like away from all the crap. Do the same with some pollen, air bubbles, fine dirt, crushed up ants, smushy bread and the most fun one of all - green slimy pond water or a wipe of algae of the fish tank wall - its like Men in Black 4 in there.
Things that are present in their millions are usually normal unless you have a serious disease issue so lets go through the slides (Myzo, correct me where you see fit). Its a lot harder looking at someone elses pics so I may get some of these wrong
1. green arrow - damaged big pollen grain - distinct wall, crumply appearance like a deflating bag of air - parasites are proud of their appearance - they are mostly smooth and well groomed
red arrow - urates - common, often variable in size (parasites don't change sizes)
2. Look over to the right where the contrast is better and you'll see the spoke wheel crystalline structure of the urates much clearer.
3. Red arrow - urates, green arrow - air bubble, blue arrow correct . Focus up and down on the air bubble to check - as expected they will change in size and clarity as you focus as you are focussing on a sphere of air.
4. Correct
5. Bit out of focus but looks like a slightly rotated pollen grain - they are often quite dark and this looks like one of the mickey mouse pollens from above.
6.Looks like a single plant cell thats come adrift
Have fun
Danny
. Good tip about getting to know the background material 
