There is no right or wrong way to do it.
As for mono or flouro leader, the difference between them is so minute in sink ratio that it's not really worth worrying about. I've used both and it hardly makes a difference. What may make a bigger difference is the pound test of that leader. I like to use 20lb leader material, it's stiffer than 10 and 15 and it will hold up against the abrasion and fins of a big red. Unless you are fishing shallow oyster beds, you really don't need the fluoro leader. 20b mono will be just fine for almost everything.
Many will join a main line to a leader with a uni to uni, crazy alberto, nail knot, or surgeons knot.
Loop knots typically allow the lure to have better action. I use a loop knot on everything from topwaters to jig heads. A properly tied loop knot should only be about an 1/8th or 1/4inch in diameter. it should not be so big that it fouls the trebles.
Hope that helps, always feel free to holla at me with fish finding questions...
tobin@troutsupport.com