Your objective is to get a monthly ride income of $10,000. Before everything, set research to only Shops/Stalls. You will need the Cash Machine later on, and it is quite deep in the research tree. Start by building a Wooden Roller Coaster in the front of the park, and charge about $4 for it. You may also want to build boats etc in the front to help get in a little more cash. Try not to go over the $10,000 loan at this point. After enough cash is made, build another relatively cheap ride (such as the Spiral Coaster) near the Wooden. Make sure to hire staff and place shops as needed.
Once you have enough money, place a few smaller rides and build another roller coaster. Working in a circle around the park is a good idea. You should build roller coasters that can be charged at least $4 for, and try to keep their hourly profits above $2,000, which shouldn't be too hard.
By now, a good amount of cash should be coming in, so maximize your research if you haven't yet got the Cash Machine. Once it is researched, change the research priority. Often researching the Log Flume is a good idea, then setting it to roller coasters will give you more freedom in your choice of rides.
After the fourth or fifth roller coaster, money should be flowing in rapidly. Take some time to place smaller rides and pay off some of your loan, which by now could be $20,000. Put research entirely on roller coasters at $400 per month, and try to get the Twister Roller Coaster. After you get this, build a good Twister Roller Coaster and charge $5 for it. Pay off your entire loan, and accumulate a few thousand dollars.
After you have several thousand dollars to throw around, build a very large Twister Roller Coaster and charge $6 for it. If its hourly profit can hit $12,000, victory is imminent. Check on your monthly ride income, and if it gets to $9,000, you only need to build a couple more small roller coasters, and then you should achieve your objective.