Play testing a deck is something that must be done in the game and some people say they do it, but never effectively. While play testing is a long and tedious task, it must be done to get your deck into tip top shape and to improve.
Lets begin by explaining what play testing is. Play testing is basically playing a deck and your testing out the deck and its performance seeing what works and doesn't so in the future you can change it to make it better. Most people at this point probably say they do this, but to be honest they don't. I am not saying no one play test, but from what I have examined people don't tend to play test too often. The key part is changing cards within your deck which is something people do not do.
Now, lets talk about how we can play test. My personal technique for this is to play the deck in matches and play 10 matches. That is anywhere from 20-30 games which is a lot with a deck. While playing these matches at the end of every game i write down on a note pad file or somewhere what was dead in my hand, or anything that just did not function like I originally envisioned. For example, lets say I had a Horus the Black Flame Dragon Lv 6 in my hand and my original thought was to combine Horus the Black Flame Dragon Lv 6 with Red-Eyes Darkness Metal Dragon for 2 strong monsters and then to recruit into Horus the Black Flame Dragon Lv 8 for protection from spells. All game though, I couldn't get Red-Eyes Darkness Metal Dragon out all game, I would mark the Horus as dead. Simply all I do is just mark it on the file and move on to the next game since it was dead all that time. After those 10 matches I go back to my deck and go into that file anything that was marked dead more than 5 times is gonna be cut, and then just move from there. The theory behind this is that cards are sometimes dead sometimes like Onslaught of the Fire Kings, but they are just to strong not to run. Moving on, maybe you do not wish to remove that dead card, then what you can do is cut down the number you run, for example in my spellbooks I tested 3 Spellbook of the Master and found 3 was just to clogy so I bumped it down to 2 and it worked more effecient. So, at this point you should have removed the cards that were dead or cut them down and at this point you try to find cards that can benefit the deck more and just repeat the process of playtesting.
Now this lesson is long, and may be confusing so if you have questions on something or need a better explanation just pm me on dn or here and I can explain it better. Till next week, I am dark magician 85 and this is my lesson.