well, now I have the knowledge about how endurance really shall be played. :P I'm assuming the reader is the GC0 geek that have managed to earn at least 100k exp at #1 endurance, so he does know the basic principles of endurance.
The very first thing you should care about is the mana trap system. You need at least one R/B trap at the very start of it, a R/P trap at the end of it (or anywhere inside), and as much R/O traps as you can muster. Make sure you always have a grade 1 orange and a grade 1 red stashed in the inventory or maybe even in a tower, in case you would accidentally combine your R/O with your last orange or red in the inventory. This is true for levels that don't give orange and red gems at creation, but is a useful practice for any other levels anyway.
Your first orange gems can go directly into traps, unless you are unable to produce oranges at creation, if so, your grade 2 orange should go for transmutations, to turn three other grade 2 gems into orange, then you just fill the other traps with these. One gem should be stashed and untouched, of course.
Next thing you should do is angering. Every wave that will come into the playfield must be angered, and the more times the more traps you have on the path, so all traps should work constantly. You shouldn't over-anger though, your traps should be capable of hurting the monsters, at the minimal rate but anyway. Use grade 1 gems for first several waves, you need the quantity to fill the traps with work, as well as you need them to be armored enough to survive the traps, so they will all produce mana. Also at first there should be a tower or two close to the wiztower to get rid of stragglers who would manage to survive the traps, to avoid the loss of mana due to banishment.
Next, at wave 4-6, depending on your success with mana gain, you should turn your trap gems already placed into dual R/O, to gradually increase their damage and number of targets, as well as range and grade. Grade 3 is in fact enough for this purpose, you can super-gem them already, but you may increase the grade if you feel like it. You will normally follow this strategy: create a bunch of grade 1 gems (15-18, maybe more), then separate any red and orange into their own rows, then bomb all the other rows (except the rows where you store gems you can't get by creation), 2-3 with red, rest with orange. Then combine a grade 3 or 4 gem out of grade 1 gems, then combine that gem with all the remaining transmuted grade 1 gems, leaving one red and one orange intact for later use. Then you put it into a separate trap, it should do some 10-20 damage per hit and have some 3.0 mana leeched per hit.
Whenever you see your mana supply rock upwards, use mana pool spell. This is essential, it gives you more mana from traps, thus accelerating the gameplay.
When you either have filled the entire path with R/O traps, or you feel that you don't need any more of them, you create one single R/O gem of the exceeding grade (4-6) and start super-gemming it until it will hit the topmost speed and range, it should also hit the topmost specials value by that time. Raise orange special first, once you hit 8.4, use red gems to pump the supergem. Put that gem in your very last trap you already have. This gem should do some 30-80 damage while in trap and have topmost speed, depending on your skills. Now you can anger monsters up to 50 armor, which means 12-10 times depending on wave number and monster type. You will have enough mana from this gem alone to produce another such gem, out of the one you just exchanged for the supergem. Repeat until all traps will be filled with R/O supergems. Initialization complete.
After you reach this state, create 1-2 R/P supergems with the same method, place them after all of the mana traps, or instead of any if you don't have space left :) These will soften the monsters for the second pass, so your mana traps will actually do some killing. By this time you will have enough mana supply to anger any wave with grade 6 gems to the requested amount of armor. If there's a giant wave approaching, and its number is still below 30, you can anger it beyond any measure, say 15 times by grade 8 gems. Yep, that's expensive, but you'll beat up way more mana and a real TON of score just off this wave, and they are so slow that you will have a lot of time to prepare your defences. I'd like to warn you though, 1M is a critical point for any defence, so you should keep your eye both on their HP and their armor, 200 armor is a very big amount, though you can cope with it by building 4-5 more R/P trap supergems.After this time you're on your own, but you have a very tough base and mana supply, so you just have to time yourself while you'll build grade 10+ defencive gems, either R/Y traps or any kind of dual gems for towers, with R/O you will need grade 11 to reach top speed without any supergemming.
This strategy can be used outside endurances as well, you will just have to anger the last waves 1-2 more times, since you'll not receive additional load after they will appear. I have used this method at one of the worse levels at tier 2 normal game, and within 26 waves I have earned 500k exp (not if I needed them...). Good luck :)
