Since the magnet monsters are good at sending cards to the graveyard, use it together with some support spell and traps and it can help with summoning Gaia Plate easily. Gaia Plate can be very dominating due to it's main effect, making it difficult for your opponent to get over it, and destroying your other monsters will only help maintain it longer.
The main win condition of this deck is through Gaia Plate. It has a powerful effect that halves the attack of monster that it battles with, has high attack, and can also be special summoned. Your opponent will need to have a monster with 5,600 attack just to crash into your Gaia Plate (6,000 if you have Wasteland field spell). Even if it's switched to defense position, your opponent needs more than 2,000 attack just to destroy it (2,400 with Wasteland active). Combined this with support monsters and spell/trap cards to maintain him on the field, or end it early using Anti-Magic Arrows.
Specializing in sending cards to the graveyard (including itself), this helps put some fodder materials into the graveyard to set up special summoning Gaia Plate.
Beta The Electromagnet Warrior: First effect will activate on summon, even if it's Floodgate Trap Hole'd. Normal summon this to add a delta from your deck. Its second effect lets you use it during your opponent's turn as a quick-play effect type, which can be effectively used if your opponent targets it with card effects, or about to destroy it. You can switch it out and special summon Delta from your deck, which will activate Delta's effect to send a magnet monster to the graveyard.
Enemy Controller: Has always been a good versatile card that you want to bring multiple copies of. It's to help with some protection, or go on the offensive with tribute taking your opponent's monster. With the help of Anti-Magic Arrows, you can enter battle phase to activate Enemy Controller, and chain it with your Anti-Magic Arrows to take control of your opponent's monster without your opponent being able to react. This can catch them by surprise and be able to go for a quick win.
Downbeat: Use this card to tribute any Magnet Warrior and special summon Beta the Electromagnet Warrior from your deck. This opens up a lot of opportunities for combos with Delta and can potentially thinning up to 4 cards from your deck.
Powerful Rebirth: Can be used to revive any Magnet Warrior from your graveyard but is best used to revive Beta the Electromagnet Warrior or Delta the magnet Warrior, triggering their effects and searching out more cards from your deck.
Both Storm and Anti-Magic Arrows can be good if you already have high enough attack to go for the win. Storm should be used more carefully if you are using a skill, or a field spell card since it will also get destroyed. Anti-Magic Arrows often catches people off guard and can potentially win you some fast and easy win.
Good for throwing out a monster from your deck. This helps put some fodder material to special summon Gaia Plate, but also thinning your deck, as well as preventing your odds of starting with a bad hand where you don't get a low level monster. Can potentially be a dead card if you don't have at least 2 of the same normal monster in your deck though, so it's good to remember not to use Beta/Delta to throw out different variations of magnet to the grave.
Backrow destruction and mills your deck during the end phase.
Other useful skills
Last Gamble (skill) Can be used in your Main Phase, starting from the fifth turn. Upon activation, reduces your LP to 100 and discards 2 cards from your hand. You roll a die and draw that number of cards. This skill can only be used once per Duel.
Gaia and Lyla are the best URs from the box besides the Dark World cards if you are interesed in building that deck. Volcanic cards are meh.
I got up to Legend 2 with this deck (modifications aside) relatively easy,you will have a hard time beating Amazoness. I didn´t push up far from L2 but I am sure the deck is capable of reaching KoG. Really fun deck, give it a try if you can.
You have a slightly higher than 1/5 chance of opening it with a 20 card deck. That isn't especially low, of course it's going to come up more often than you'd like. (And really, it's just the fact it's such a bad card that makes it stick out. I'm sure you start with Beta the Electromagnet Warrior just as often, but don't register it because you WANT it.)