single target: thunder2 -> fire spam til low mp -> transpose -> reapply thunder -> blizz1 or scathe til full mp -> fire spam til low mp -> repeat
aoe: fire2 til low mp -> transpose -> blizz2 until full mp -> repeat
Transpose loses a lot of usefulness once you get fire3/blizz3. Those will remove the other's stacks and put you into astral3/umbral3 respectively. This means that at the end of your fire rotation you can blizz3 to get full ice stacks, and then fire3 once you're at full mp to get back into the fire rotation.
When in doubt, throw fire at things. Sleep is also handy when you're soloing.
Also keep in mind that this advice is specifically about leveling rotations. The class changes quite a bit, so keep an open mind and read the tooltips as you level.