petere,
To avoid running out of credit (or, even better, to avoid going into debt), you must both make money and keep expenses down. At the beginning of a mission, the main expense should be construction. Soon after the mission starts, you'll want to build a money-making industry (gold mine(s) and palace), provide protection (fire house and architect post), probably give people water (water supply), maybe start food production (hunting lodge(s) and granary), and house enough workers (who will be about 40% of the population) to staff those buildings. If you don't have enough money to do all of those things right away, then scale back your plans--perhaps build fewer gold mines or delay starting food production.
It's not necessary to build a lot of gold mines in Thinis--I built 6 (and went into debt for a short time), but 1 or 2 should be enough. You could start by building housing and roads, and then placing a gold mine as soon as immigrants arrive. When the first gold mine is fully staffed, you might place a fire house or architect post or police station (if the Risks/Fire or Risks/Damage or Risks/Crime overlay shows significant risk), the palace (if the mine is close to finishing production), another mine, or a hunting lodge (if you intend to start food production quickly). Continue to place useful buildings when the existing buildings all become fully staffed (or even sooner in an emergency), but keep an eye on the treasury--if it's getting low then wait for a bit while the gold mines fill it up.
The mission will finish when the city has 10 ordinary cottages. At some point (probably after you've mined some gold), you'll receive a message about religion. Sometime after that (perhaps after you've built a temple), you'll receive a message about entertainment. Water, food, religion, some entertainment, and a not-too-undesirable neighborhood (which may be improved with nearby temples, shrines, and some other buildings) are enough to evolve houses to ordinary cottages. If you're not sure what to do next, check the mission briefing (click on the ankh symbol).
By the way, the first 5 missions are "tutorials", which require you to complete intermediate goals before new buildings (that are required to complete the mission) become available. Starting with the 6th mission, Timna, you'll have everything that you need from the beginning (except that sometimes a required trade route is not yet available).
[This message has been edited by Brugle (edited 01-06-2004 @ 02:20 PM).]