First of all, I would like to say that I am not the best player in the game by any means, and these tips are not for every strategy/deck, there are always exceptions to what I say and probably other(better) strategies than these. However these 7 tips are well thought out and I believe they are the fundamentals of advanced play. Read them, use them, agree with me, disagree with me, whatever. I'd love to read feedback so throw some on here for me after you finish reading.
my first big tip is learn all the rules and how to use synchro and xyz monsters - they are the new era of yugioh and the two types are incredibly fun to use and are incredibly powerful.
second tip, understand the term "hand control" aka "card control"
hand control is when you have more cards in your hand that your opponent throughout the duel. the idea behind it is that the player with more cards in his hand has more effects and options to work with and battle the opponent. if a player uses his entire hand up and can only draw 1 card per a turn from there, he's screwed. this is why i use a lot of cards that send cards from your deck to your hand, constantly. examples of decks based around this are black wing decks, gadget decks, herald decks, etc.. the more cards you have in your hand over time, the more likely you are to create powerful moves and win down the road. read the paragraph at the end to understand this even better.
third tip, understand the term "field control"
field control is when you have the biggest field presence, whether that is having lots of monsters with good effects, or 1 monster that is very powerful and hard to destroy (such as blue eyes shining dragon). it is important to gain field control fast and hold it. i use a lot of monsters like kagetokage and tin goldfish to get more monsters on the field per turn. even though they are weak i can use them as xyz material for something strong.
fourth tip, the back row (aka spell and traps)
my spell and traps consist of all the "staples" to a deck (or cards that are considered necessary to use in every deck) such as dark hole, heavy storm, monster reborn, mirror force, torrential tribute, book of moon, pot of avarice, mystical space typhoon, and bottomless trap hole- option staples are the counter trap cards with "solemn" in their name). from there i only add spell or traps that help my deck's theme.
fifth tip, de-clogging your deck
having a very steady deck is very similar to understanding card control. the idea is that you want to draw a useful card that you can use the turn you draw it, every time you draw a card. this means you must go into your deck and remove any/every card that sorta "clogs" your deck up. these are cards that you have a hard time using when you draw them, such as ritual monsters and really strong monsters with horrid summoning conditions (such as blue eyes shining dragon). the closer your deck is to 40 cards, the better.
sixth tip, speed and the extra deck
"Speed" in yugioh is the ability to maintain field control and/or hand control. your deck's "speed" is determined by how fast you can get monsters on the field and still maintain hand control (this is why i like to use red/yellow/green gadgets). the extra deck can only be 15 cards so it is essential to A) fill it and B) pick wisely. don't pick the hardest extra deck hardest to summon because they are awesome. pick cards that you know you can summon easily with your deck (my gadget deck has an xyz deck mostly filled with rank 4 xyz monsters). really research what cards you want to put into this deck and make sure that they flow with your normal deck's theme.
my seventh tip, understand "1 for 1+"
if you are determined to maintain card control and field control, then you must understand when to use cards to keep control. the term 1 for 1, means one of your cards for 1 of your opponents cards. an example of a 1 for 1 is a mystical space typhoon. you use 1 of your cards to destroy 1 opponent card, aka 1 for 1. now if you want to gain a card advantage you should focus on lowering your opponent card advantage with cards that are more like 1 for 2 or more. an example is dark hole, when used correctly it can really lower your opponents card advantage. for instance if you have 1 or even NO monsters on the field while you opponent has 2 or more, activate dark hole. say opponents has 5 monsters and you have none, activating dark hole is a 1 for 5. you get the idea!
These are my tips for yugioh success, if you follow them i guarantee you will be a much better player in general.
**Tip Number 2 (hand control) continued**
every card you play can be thought of in terms of a "card control number (CCN)." every card starts as a -1 CCN because it costs you a draw phase. the cards effects to add cards to the field or hand then add or subtract from its CCN.
for instance normal summoning dark magician is -3 CCN, -1 for drawing him, -2 for tributing 2 monsters from field to grave, +1 for adding 1 card (your dark magician) to field, -1 for removing 1 card from hand (that dark magician). -1-2+1-1=-3
whereas a card like monster reborn has a neutral CCN, -1 CCN drawing a card, then +1 CCN adding a card to the field (monster reborn) -1 moving monster reborn to grave, then +1 adding 1 monster to field. -1+1-1+1=0
And lastly cards like (this is just an example) pot of greed are a +1 CCN: -1 for the draw, then +2 for adding 2 cards to hand. that is why this card is forbidden, it is such a great +1 CCN. -1+2=+1
now combine CCN with the idea of tip 7 and lowering your opponents CCN. for instance, a cool card to use is morphing jar if you have a small hand and your opponent has a large hand. say your hand is empty and you opponent has 5 cards in their hand when you activate his effect. you draw 5 cards (+5), while your opponent discards 5 cards then draws 5 (neutral).