IF your goal is gathering coins fast, and even if you aren't interested in space right away, the planetariums are the best shot at 2000 coin collections when visiting neighbours.when i first started playing i 'didn't get' the visiting neighbors thing... i would go on a visit and click on 5 random buildings... then i saw the post about looking for neighbors with planetariums, and so began my space quests...
i see Chloe's post about using planetariums for gathering items for high dollar collections, but if someone is not interested in space, what should they be clicking on in their neighbors cities?
When you start getting near 100 launch ready kits, open them up - even if you aren't ready for space. By doing this, you will start building up your fuel (there are 8 items the launch ready kits can drop so it will be a long time before you hit your 100 max on the fuel items).
Of course, sometimes you'll want/need to tap on other things to complete missions and perhaps you'll want fuel quickly to speed up flights so tapping on stands is a quick way to pick up fuel units.