I just recently got back into Yugioh, and so I created a deck based on Light-monsters. To be honest, I don't really know if it's good or not. So, any suggestions would be greatly appreciated (by the way, building decks was never one of my specialties lol).

Monsters (20):
BEWD x3
BESD
Kaiser Seahorse
V-Tiger Jet
W-Wing Catapult
X-Head Cannon
Y-Dragon Head
Z-Metal Tank
Mecha-dog Marron
Guardian of the Throneroom
Majestic Mech - Ohka
Vanity's Ruler
Light Effigy
Dawnbreak Guardna x2
Royal Knight
Hyozanryu
Wingweaver

Fusions (4):
BEUD
VW-Tiger Catapult
XYZ-Dragon Cannon
VWXYZ-Dragon Catapult Cannon

Spells (10):
Ancient Rules
Mystical Space Typhoon
Pot of Avarice
Change of Heart
Pot of Greed
Level Limit - Area B
Heavy Storm
Ground Collapse
Megamorph
Monster Reborn

Traps (10):
Sakuretsu Armor x2
Numinous Healer
Nutrient Z
Cemetary Bomb
Dust Tornado
Ominous Fortunetelling
Enchanted Javelin
Jar of Greed
Spellshield Type-8

this is just kind a random mishmash of cards.

you need a unifying theme.
go with BEWD, VW, fairies, etc...

try to avoid normal monsters without a good reason for including them.

i really don't know how to help you until you pick one idea to stick to...but this won't get you very far.