First, you can start out by going to an insurance agent if you want the personal help. An insurance agent (look online for local agents in your area) will meet with you and discuss what type of coverage you want, what you want to spend and what your temporary medical needs may be, they can also discuss family coverage options. Always visit more than one agent and compare prices.
Now, if you do not want to go down the agent path, you can always shop for temporary health insurance yourself. Make sure you know what you're buying. What type of coverage are you paying for? Will it just cover emergency medical expenses if you're in a car accident? Or will it cover regular doctor visits and prescriptions? What type of coverage you buy is up to you. Popular health insurance providers are Aetna, HAP (Health Alliance Plan), and Blue Cross/Blue Shield. There may be others that are popular in your area.
Next, if you've just graduated from school and are expecting to find a job with health insurance benefits in the near future, there are many temporary options that cater specifically to recent graduates. These plans usually only cover catastrophic injuries and not preventive care. Many schools sponsor these programs, so it is worth asking your adviser, health center or other people at your school whether your school has a program, this will probably help you out cost wise. If they do not have a program they are involved in, www.gradmed.com is an option. Any of these plans will offer temporary health insurance coverage of varying lengths of time (you can choose). After applying for one policy and having it lapse, you'll have to reapply for another policy each consecutive time.
Finally, make sure you pick the right deductible amount. The higher your deductible, the lower your health insurance rates are, the lower your deductible, the higher your health insurance rates will be. While a low insurance rate is tempting, make sure you are picking the right deductible amount. I generally go with a deductible in the mid-range. Always keep the amount of your health insurance deductible on hand in case of emergency. I suggest opening up a separate checking account for just this purpose. Keep emergency funds in this checking account, including the full amount of your health insurance deductible and never touch it unless needed.