I wouldn't recommend backtiming unless you are an experienced defender - you can easily lose nukes on pre-stacked villages if your backtime is going across a large distance. The only time it is worth the risk is on packet worlds, backtiming nobles. This is because killing nobles at home does the enemy a lot more damage than them killing off the nuke(s) does to you.
Dodging should be used when you have a small number of ram-speed attacks that look likely to be fakes at a village. NEVER use offensive troops to stack a village. Always dodge with these where possible. If you lose a wall from a well-hidden nuke amongst fakes, so what? You can still hold a village effectively without a wall. You can't without troops.
Stacking. If you can get large amounts of support to a village being heavily hit, this is generally (not always, but generally) the best thing to do. Whether this is your defense, or tribal/friend support. It will demoralise the enemy if you can take out their nukes, as they can't do too much. I would generally advise 3 full defensive villages minimum as a stack, as this way the losses you gain will be spread between villages, and on average their nuke losses would outweigh your defensive losses depending on how many defensive villages you can support the target village with.
Sniping. This is the single most valuable technique in defending. In both meanings of the word. Let's cover the first meaning - supporting a village between nobles landing. This is a great way to hold a village with minimal troops needed for a period of time. Eventually if they keep sending nobles you will lose it. However, each time you kill off a bunch of nobles it puts the enemy back several hours. There is nothing nicer than seeing a nuke or a noble go splat.
The second meaning I prefer to call re-capping. This method is the idea of letting yourself lose a village, but retake it straight after.This can be useful for holding villages - particularly if you pre-noble the villages before the enemy's train lands, so that they overnoble. Again, more effective on packet worlds than coin worlds.