Once you create your account your warlord will be invisible for a period of time. How long you are invisible for depends almost entirely on you. You will remain invisible until one of the two following criteria is met:
1) You make an attack and win. If you attack and lose you will remain invisible.
2) You kill a certain cumulative amount of troops when you attack (currently nobody knows how many troops need to be killed in order to trigger this clause).
If you reach 999 APs you will remain invisible but your account will “freeze” ie you will not receive any tic updates.

In order to make the most of being invisible there is a tried and tested sequence of building that you should follow.
Buy the following buildings in this order:
1) Market
2) Fort (required to build an armoury)
3) Armoury (required to build a treasury)
4) Treasury

Obviously to buy each building after the market you will need to save up until you have enough gold to purchase the building you need. It will take several days to save up enough gold, so you can easily leave your account and check it every day or so.

Once you have built a treasury you are ready to make the most of being invisible. Your objective now is to milk your treasury for all it is worth. You will need to begin saving gold and not spending any of it until you reach 110,000 in your bank. As soon as you have 50,000 gold in your treasury you need to build a barracks.

Once you reach 110,000 you will have to be quite active to make this worthwhile. After your gold on hand passes 110,000 you will lose 500 gold income per tic on an open market / 125 gold per tic on a closed market. However… if you log on as often as possible and buy a cheap unit (such as a level 1) your income will return to its usual amount, decreasing again after the next tic. You will need to keep doing this until your gold on hand reaches the magic figure of 350,000. Why is this figure magical? Easy – there is a cap on how much gold a treasury generates each tic, that limit is currently set at 3,500 gold per turn. Once you have reached this golden figure you can keep your gold on hand to 350,000 and really maximise your treasury.

It is now up to you what buildings you get and in which order but some things I believe are a must. Morale is now effected by your armoury, ie better equipped armies have better morale. One thing you will notice is that your morale will start to get quite bad the longer you are invisible for. To combat this you will need to build a level 2 armoury and buy some armour and weapons for your troops. Each time you buy a new building you should spend a little on buying some metalwork for your troops. You can also buy buildings for level 3, 4 & 5 troops. These troops will also help your morale out.

By the time you come out of invisibility you should aim to have at least the following buildings:
Market lvl 1
Barracks lvl 4
Armoury lvl 2
Fort lvl 2
Archery Range lvl 1

Once you reach 999 APs you have two choices:
1) Spend down and start attacking!
2) Don’t spend down and try to stay invisible longer.

To stay invisible you will need to pick targets to hit that you have absolutely no chance of winning, such as those right at the top of your attack pages. As long as you keep your AP total below 999 you will continue to get updates each tic. Take care not to hit the same people every day for high AP hits. People do not like getting whacked hard by invisible players and will remember your name and will be looking for a little payback once you are out of invisibility.

It is still possible to have a high placed finish if you go for an invisible start. I have finished in the top 30 having used this strategy before. Your success will come from hunting runners and minimising how much gold you lose.

I will add that now you get a free barracks at reset things are speeded up somewhat! On the reset for the Firestone era I was able to get 8 barracks, 3 forts, 2 shrines, and 2 divine meadows.

Obviously playing Fangs helped due to the lower building costs... also not being a donor helped so I was able to stay invis for a couple of days longer due to not getting the bonus APs automatically.