Well, here're some tips, for a good deck .1)focus on a specific type, or attribute monster. In my experience are LIGHT, DARK, spell caster, fiend, dragon, and warrior.2) have 40-42 Cardin the deck.
It depends on your battle style because my m8 uses spell traps and mag a lot but I att quickly without caution, to make the best deck find your battle style the keep thinking u'll get it soon. I would have to say machines(Zane's Deck),dragons, or spell casters are the best decks. But those just suit me best otherwise depend on your on battle style, monster type, attribute, and strategy.
Personaly I would go with dark Zane and but i don't mean any of those metal dragons or what ever I mean pure destruction and darkness only use dark monsters pack 10 traps and spells don't forget cards that boost monsters ATK and above all never forget a swift GIA the fire knight and a fiend megaweber P. S please don't mind my spelling but if you do I can't blame ya. If you can't find what deck you want just cheat) but i recommended dark / dragon.
It took me ages to find my right deck I made around 10 different recipe, but I then found adding attribute monsters with affects that help one another is a good thing to use E. F buster blade has an effect for every dragon in the graveyard you get 500 extra at take points so I use warriors and dragons :P. The good thing about a dark world deck is you can have four of your strongest cards on the field within to or three turns.
I used a deck that consists of level 3 or lower monsters and have gravity bind and level limit area b with me and different dimension capsule and sealed golden coffin to get these and I only lost once to Jaden. There's one deck I made that almost never loses; it has The Horus the Black Flame Dragon Cards, Royal Decree, Lots of nasty effect monsters(Man-eater bug, Foodora, Night Assailant, ECT), and many powerful spells to stop just about anyone I face.
Get spells, traps, and monsters that clear your enemies field and prevent attack. Magician of faith, penguin soldier, swords of reviewing light combo.
Morphing jar and card destruction work well too if you can flip it on your turn. Besides this get a good balance of cards in your deck (around 40-45 cards) preferably over 40 because opponents usually have 40. If you have run out of strategies, then you should play good defense monsters and run down the opponents deck.
Always have some strong traps like magic cylinder or mirror force possibly rage brake. The deck I used is mostly consisting of special summon, so it's easy to have many monsters on the field at same time.
I like a deck which can wipe an enemy out at the least time possible, but magic and trap is my weakness NOTE: By having 2 magicians Valkyrie on your field will make you invisible from battle.
Strategy: Stratus(Airman) play and keep hand full. First one focuses on special summoning quickly plenty of warriors and the Mystic Swordsman.
Other deck focuses solely on keeping the duel going and going until the opponent runs out of cards, or you deal the damage to his life points without any attacks to you. Cards to mention:Wall of Revealing Light, Level Limit Area B, Wave-Motion Cannon, Romanian etc.
Here are some personal receives that are general beating anything but few weaknesses the main thinking of some of these receives is to have equal chances to draw a monster or spell&trap card, so the main mix is 20 monsters and 20 spell&trap(usually 10spell%10trap) There are 2 types of black flame dragon receives I use one is pure LV and the other based on negating spell trap and effect monsters lacks a bit attack boost, but I think you get that from 3000 of monarchs attack.
You can also use the dark magician of chaos damage loop, exchange spirit, ring of destruction+ spell pain/barrel behind the door, or butterfly dagger Elma. It consists powerful spell card like Final Countdown, Wave Motion Canon Etc.
I tend to use monarchs they make good cards for sticky situations A really fun deck that works, but needs more testing, is my destiny hero deck that spams dark paladin by using cards like emblem of dragon destroyer to get buster blade to hand, works with diamond dude as well, and use too table of contents with skilled dark magician to summon dark magician, plus it thins your deck.
XD joking, clogs up sometime but that's why I run Marshmello and spirit reaper. I tried to make this deck based on the 2012 ban list, so you could, if you wanted to add more chain strike and Obama trio instead of some drawing cards.
Just don't put in too many spells/traps/high level monsters or all find ourself with a useless hand very often. Also don't use reload or magical mallet because if you put a good deck together, then you won't need them.