Once you get to Pirateville or the ship town. The trick is to ALWAYS upgrade the potion maker to at least the 2nd upgrade.

ALWAYS advertise with flyers, use as many as they let you without them being junk mail.

When the days are high (with one or more potions) position the trolls in every competitor's doorstep and advertise with a sandwich board dwarf on the most traffic-ed area.

At the beginning of every town, ALWAYS buy enough for 20 potions, so you don't have to worry.

Do not restart the level, you will always have to have the Fairy Godmother pay off the loan shark and once this happens, you're back in the game. Make sure that you pay him BEFORE this happens, as much as you can, so that you don't get him paid off right at the beginning or you won't survive.

These are the competitors in the order of knocking them down:
(Easiest to hardest)

1. Bearzinis
2. N.H.S. Princes
3. Dragons
4. Cows
5. Sneerworth

Do not advertise ALL the time, if the day has low potion users percentage, just use the troll on the doorstep.

These seemed to always worked for me and I finished the game.

OH!! On the last 3 levels, make sure that Mr. Sneerworth stays as far away as possible. DO NOT LET HIM WORK IN YOUR LAB AT ALL!!!!