Basic:
-Scouting. You must scout your opponent's tower placements and observe what they send. This is key to determining what to send for your offense and what to build for your defense.
-Communication is VERY important especially in this game or in any team. As a general rule, bigger teams will make the game harder depending on how well you communicate with your teammates (more teammates = harder to coordinate).
-Don't send your main offense too early. At least send a bit before Armageddon or after.
-Upgrading your mine quickly to the gold block (level 3). This is top priority.
-If you need XP, send cost-effective XP mobs every 15 seconds (e.g. zombies, spiders, caves).
-Don't ever buy personal weapons (i.e. bows and swords). They deal way too little damage for their cost. You're better investing in more defense, a stronger offense, or more XP.
-Don't bother placing turrets. Their damage output is so low for their cost that just 9 level 4 archers beat it in terms of damage per cost.
-Start learning about build orders. I wrote a guide a few months ago detailing this:
https://www.cubecraft.net/threads/h...ower-defense-build-orders.179951/#post-748497
-Certain towers are strong against other mobs, adequate against others, and weak against others. For example, the necromancer tower is strong against giants but weak against swarms and flyers.
Intermediate:
-Starting from here on out, your XP mob should be zombies only.
-Use freezing potions against tougher waves like air units and giants.
-Support your offense waves with speed (exception: giant, not affected by speed) and regen when needed.
-Save some coins for emergency defense. At this point, you should gradually transition from heavy to lighter, but retaining effective defense depending on your opponent's mob composition. That is, start with a small defense but build more only if your opponent sends in tougher units.
-Consider build spots in maps and take note of any effective chokepoints.
-By now, you should have a basic build order. Every game you may have to change it depending on your opponents and mob/tower composition.
Advanced:
-Use meteor potions against air units, zeus potions against multiple giants.
-Optimally place towers such that you minimize defense costs while maximizing its effectiveness.
-By now, your defense should depend entirely on your opponent's mob composition. That is, that's maybe 1-5 towers to start (well-placed) and then respond as you would usually depending on their mob composition (e.g. if they send air, you respond with archers).