Total Score = Citizen + (Value of cargo ships)/300 + Master builder + Generals + Scientists

Citizen: 1 point for each citizen you have.
Value of cargo ships: The total amount of gold you have spent on cargo ships.
Master builder: 0.01 points for each resource you spend building, so a building costing say 700 wood and 300 stone would give you 10 points.
Generals: Your military score, 0.02 points for each resource you spend building troops. When troops die you loose points here.
Scientists: 0.02 points for each normal research point you spend, this increases if you research future researches.

The score system is fairly balanced, troops give more points for resources spent, but they die frequently. Research gives more than building buildings, if you compare the costs, but the buildings will enable you to grow quicker overall. Buying ships also gives you a lot of points, and the more ships you have, the more you can raid. My advice is to try and balance it all, and exactly how you do it depends a lot on the players around you. In general though, you want to focus heavily in research the first few months till you get the important researches done, steam giants will help you a lot if you get them before most other players.

When it comes to military, unless you’re in a war, don’t build more military than you need to pillage and defend yourself with. That can mean a lot of troops or hardly any at all. If you’re in a very quiet neighborhood you don’t need much defense at all, only enough troops to raid with. You need to pay upkeep for your troops every hour, that hurts your growth, so that’s why you don’t want too many of them.

To grow fast you need to get a lot of resource income from pillaging other players. In general it’s not a good idea to pillage other players on your island, as they will hopefully help you in the future by donating to the mill and luxury resource at your island. If they don’t want to donate however, pillage them as much as possible. Have high level hideouts, both for defense and also to be able to spy on potential pillaging targets efficiently. Don’t make attacks where losses will be high, you need to both pay resources to rebuild your lost troops as well as loosing some population for a while. In general with troop building, don’t build a bunch at a time, you want to have close to max population all the time to get maximum income.

One more thing, always have your mills and luxury resources at full production. An idle citizen will only give you 3 gold per hour while a citizen working in a mill will give you at least one building material per hour. You can sell resources for 7 or more gold easily, so it’s definitely the best place to put your citizens.

Risk on a spying mission can never be lower than 5% and never higher than 95%. The formula is:

Risk % = MBR + CR + SOD * 5 + THL *2 – TTL * 2 – AHL * 2

MBR: Mission base risk.
CR: Current risk.
SOD: Spies on defense.
THL: Target hideout level.
TTL: Target town hall level.
AHL: Agressor hideout level.

Mission base risk for some common missions.
Infiltrate Town: 5%
Spy Tresure Chamber: 24%
Inspect Warehouse: 30%
Recall spy: 30%
Spy on research: 40%
Spy online status : 50%
Spy on garrison: 70%

If you play around with this formula for a bit you’ll really see how important it is to have high level hideouts. Most players won’t bother attacking you if they have to waste tons of spies checking out your warehouse and army. Intelligence is really important in Ikariam for sure.