Lure or incense?

A lure (or multiple lures) are the best when you're in town.
Incense seems to be more effective in countryside.

Lure gives you typically 10 Pokémon over the 30 minute time period. An incense when standing still gives one Pokémon every five minutes so 6 Pokémon in total. If you are moving however then incense should be giving you Pokémon more frequently, but in my experience I usually only get like 1 extra Pokémon even if I'm walking, although theoretically you should get a lot more. Because of this, I think lure is more useful in most cases.

However, if you are in rural areas where there aren't any Pokémon spawns there, you have a higher chance of getting rarer Pokémon from incense. It is not enough that your 'sightings' tab is temporarily empty, you have to be far enough from any spawn points.

According to Pokemon Go's coding Incense will spawn one Pokemon every five minute if the player is not moving around. However, the spawn rate will increase to once a minute if a player travels at least 200 meters between spawns. So, to maximize Incense's effectiveness, a player needs to be moving at a speed of about 7.5 miles per hour...the speed of a fast jog.

Hypothetically, it's possible to catch up to 30 Pokemon while Incense is still working. However, between Pokemon Go's glitchy tracking system and players stopping to actually catch Pokemon they find, you're more likely to only get 10-15 Pokemon by using this method.

Also if you set auto time and auto time zone off in settings and pop your incense then switch your time back between 35-60 minutes you'll glitch the system to give you upwards of 60 minutes timer instead of the normal 30.

This also works for Lucky Eggs just so you know.