Upgrading a Town hall
When you upgrade a town hall you always have to max out pretty much everything. So if you have a town hall 6 click on everything and press upgrade. If it says you need a town hall seven to upgrade this you are good. But if it allows you and you have enough loot or not, you should probably upgrade it before your town hall.A town hall 7 takes 6 days so if you upgrade it and only have an archer tower left you are good as long as it finishes before your town hall.