Hello! Welcome to Sparta!
In the upper levels, the game will ask you for more and more resources and drachmas to upgrade your buildings... no worries! you can have them all through participation in tourneys. This is a strategy game, so think carefully about what you are willing to improve first :)
The best thing you can do to get a lot of tips is joining a coalition!
Good luck!
You will need Drachmas but they are available from tournaments as stated above by Venesa ( moderator)
You need to watch out for few tricks in order to help you save the amount of drachma you spend.
If you are about to build towers would be a good idea to wait and pile the drachma and get the offer which you can build a gate and a wall at a very low price.
Decide what strategy you will use during your play so you can invest wisely your accumulated Drachma.
Towers they get to generate points for the enemy while they get destroyed if no defense is available in your city but can get some support while you defending your city by being the first to get hit instead of direct hit to your army.
Getting your Sappers will benefit on reducing the time spend to repair the towers once they get hit.
When you offline and your city gets hit if your towers get damaged your team mates can repair them and usually 1 team mate can repair 1 tower only/ day; otherwise you need to log in the game to start the repair of your towers.
Walls and Gates they do not get destroyed and they still add to your city bonus which can make a difference in a battle.
Some players prefer not to build towers as they are visible that the city got attacked and a clear evidence of the owner not being active or online at that point.
Good luck in the game and I hope this helps.