Minimize the number of cards you put into your deck. Too many cards mean there's a lower chance of you drawing the ones you need. As for treasure cards, only put in cards that you plan on using. For example, a low level wizard does not need to fill up his side with leviathans.
When you first enter an area, go around and talk to every NPC you find. Do NOT go out of your way to do the side quests right away, however. Instead, just keep to the main quest. Often the side quests "stack" in such a way that you can kill the same mob type just once while completing 2 or 3 separate quests.
Then, as you work on the main quest, you will often find yourself completing several side quests at the same time. Once you've completed that world's main quest, go back and finish up the few sides you have remaining. This tip is especially helpful in Wizard City, Krokotopia, Marleybone and Mooshu.
Do NOT skip Grizzleheim and Wintertusk, even though they are optional side worlds. Do part one of Grizzleheim around level 35-40, it will lead to an extra spell. Do Wintertusk somewhere between level 50 - 80 because, again, it will lead to several spells, a high level minion, and all your school pets.
If you are new, struggling to make a pet, find good gear and quest solo, then find friends! Do this through team up or forum meet-ups. Your journey questing will be made much easier with additional firepower, and much more fun - new friendships are created this way~
For new wizards, always plan ahead! Put potentially good gear you receive from questing into the shared bank, so you can easily use it on your next wizard. If you want to craft and make pets, store reagents and pet drops too! You'll never know when they will come in handy.
Embrace the entire game, there are so many different things to do besides questing and PVP (crafting, gardening, pets, housing, ect) and ALL of them do there part to enhance your wizard(s) for questing and PVP. You'll be a far less frustrated wizard in the long run. And don't forget that you get SIX wizards. Explore multiple schools to discover their strengths and weaknesses and truly find your favorite. This knowledge also enhances your ability to know your enemies!
Communicate with your team. You should have a plan prepared before going into a tough battle (one that cannot be completed in less than 5 rounds), and usually it is most efficient to choose ONE person to hit while others support that person by either healing the team, boosting the hitter, or weakening the enemy (by negative charms or shields). It is not advised for everyone to silently enter the battle and blade themselves with no plan. This works in earlier worlds, but in Celestia and onward then more bosses tend to have cheats. It is also useful to have a few separate decks so you don't have to constantly change around one.
tl;dr: communicate with your team, don't just silently blade yourself. this matters more in more difficult worlds
I have been heavily involved in pve for the past 9 years. I have 9 maxed characters across 2 accounts, with 2 more accounts containing at least 1 maxed wizard each. Throughout my long time of playing this game and questing, I have made tons of adjustments to my strategies and found new ways to play. There are many things I see people doing which make their questing extremely inefficient. Below is a list of ways to begin questing at maximum speed, and bringing new enjoyment to the game.
Smaller Decks- There isn't a need to bring one of every shield, prisms for random battles, or even heals. Try to limit your deck to only what you need. Personally, for my hitting classes like fire or storm, I only have 1 or 2 blades, 2 or 3 hits, and 2 or 3 enchants. While my support classes will have a few blades to use on the hitting class.
Win fast- Your goal in a battle isn't to see how long you can last, so get to the point by using an aoe (hits all) combined with blades to defeat all the enemies.
Don't use traps- Traps are very inefficient unless it is feint on a boss, past mooshu there is no reason (except hitting one million) to use school specific traps
Don't go alone- Sure, you can quest alone, but where is the fun in that? Bringing someone can speed it up as well.
Gardening- Start gardening as soon as possible, plant Key Limes to get yourself to gardening level 5, then watch videos on how to triple stack plants (mainly couch potatoes and evil magma peas)
Fishing- Fishing isn't nearly as important as gardening, but it can still be beneficial
Training Pets- With the new hatching kiosk, there is no reason to not have a killer pet. Hatch with a really good pet multiple times and turn that pet into your own beast.
If your computer can handle it, try running 2 accounts. Always having a questing partner (yourself) is very useful and speeds it up tremendously.
Always check team up
I wish I could add more tips, but the character limit is too low :(
Have fun! If something starts to feel like a grind choose to do something else for a while. You can go back to anything and pick it up where you left off, so focus on what you feel like doing not what you think you should be doing!
Crafting matters, as you get higher levels, some great gear is crafted. This is much easier than trying to farm a specific piece and hope to get lucky.
AoE (area of effect) spells that hit everyone is the most efficient, especially if you travel with a friend (as mentioned before). Another benefit of a friend, you can finish quests faster.
Go up to everything. There are a lot of cool housing items you can just "take" from the environment, especially in Dragonspyre and Mooshu.
Tower shield is a lifesaver, if you aren't Ice, get it there. Try to build your decks for action efficiency. Passing just because you don't have enough pips is painful at times. A third blade, even if a duplicate (or triplicate) could still be useful later.