Allright, hmm, your monsters...
-1 Divine Dragon Ragnarok (It's too weak to have three)
-3 Tyrant Dragon (I just don't like him
)
-1 Lord of D (It's too weak to have three)
-1 Spirit Reaper (This is so useless/random in this deck)
-1 Marshmallon (This is so useless/random in this deck)
-3 Troop Dragon (It's damn weak! xD )
Hmm...
+2 Spear Dragon (High attack + Penetration effect)
+2 Axe Dragonute (High Attack)
+2 Blue Ice White Night Dragon (Nice effect)
You could add one king of the swamp and one polymerization.
You could not add the blue ice white night, and keep two Tyrant, but that's up to you.
-1 Dragon's mirror, it's just too much to have 3
-3 Different Dimension Capsule, if you can make ALL your cards good, you won't need it.
-2 Book of Moon (If you want a quick spell, then add Shrink)
+1 Mystical Space Typhoon
+1 Lightning Vortex
+1 Fissure
+1 Smashing Ground
-3 Sakuretsu, it's just a bad trap xD
+1 Magic Cylinder
+2 Bottomless Trap Hole
+2 Solemn Judgement (Yes, three is not necessary)
You could also do: - all traps, +3 Royal Decree, +3 Shrink.
I have no idea how many cards you would have after this, but it would make you a nice Dragon deck I think.