The following steps will help make filing a claim a lot easier for you:
1. Note the date.
If you know for sure that you've recently had a hail storm, note the date. You'll need this date to file a claim. If you didn't take any picture of the hail storm yourself, do an internet search with the name of your city and the keywords, "hail storm." You ought to find a lot of pictures of people showing the size of the hail. Save a few to show the agent.
2. Get a qualified opinion.
If you suspect you have damage to your roof from a hail storm, get several opinions from qualified roofing companies. If you are in an area susceptible to hail, you will most likely find several that list themselves as hail damage specialist. Simply tell them that you suspect you have damage from a recent hail storm and they'll be more than glad to come and give you an estimate. Always check their references, BBB, Yp.com (yellow pages online), Angie's List, Yelp, etc...)
3. Meeting the roofing companies.
When the roofing companies come, spend some time getting to know them and ask about the service they provide. Most will spend about 10-20 minutes on your roof accessing the damage. Ask them what they think and if they'd recommend that you call your insurance company to file a claim. Get business cards and any information they provide about the roofing process that they use. Ask them all if they'd be willing to be there when the insurance adjuster comes to access the damage. I think as a general rule, if they are not willing to be there, then they really don't think you have much of a chance in getting your claim approved.
4. Filing the claim.
This is the easy part. If the roofing companies recommended you call in a claim, just call your insurance company and tell them you want to file a claim for hail damage. They will then request all the pertinent dates and data from you and will probably also ask if you have any interior damage. It's probably not necessary, but when I put in my claim, I made sure that I told them that I already had several roofing companies who specialize in hail damage look at my roof and tell me it needed replacing. Also know this, in most states you have up to one year to file a claim for damage. Although I don't recommend you wait that long, just make sure you know what the date, or dates, of the hail storms. Also, don't worry about how old your roof is because it doesn't matter. The insurance company will look at your claim and settle it if you have damage no matter how old it is. The last thing they want is for your roof to fail (leak) and you put an even larger claim in.
5. Meeting the insurance adjuster.
When the insurance adjuster comes, there will not be much for you to do. Hopefully, you'll have a contractor who agreed to meet the adjuster with you. The adjuster will take about a half hour to access and (should) take pictures of any damage and then explain the next steps to you. Some companies may give you a settlement quote right then, but many can take up to a couple weeks. When the adjuster is done, your contractor, or contractors, will probably compare notes with the adjuster mainly to see if the total roof measurements are about the same. In a case where the adjuster states they didn't think there was any significant damage, ask your contractor to debate it with them. Even if you didn't have one there at the time, and you later tell your roofing company what the adjuster said, most insurance companies will send their adjuster back for a re-inspect to discuss with your contractor.
When the adjustor leaves. Well hopefully, they gave you a favorable indication about a settlement, so the next thing you want to do is make sure you get written quotes from the roofing companies you've been working with. Start thinking about which one you are going to select, and make sure you take into consideration a company's reputation and not just the price or discounted rates they're offering you. Also ask them for a discount or upgrade if you should bring them more business. If you had hail damage, then it is likely your neighbors had damage, and you might as well benefit by recommending a roofer to them.
6. Getting the work done.
If your insurance company approves your claim, you will most likely get enough, less your deductible, to complete the work. If it's not enough, your contractor should help you dispute the amount based on the work needed. Don't be alarmed if your insurance company depreciated the amount allocated for repairs because of roof age. They are just holding back some of the money until the work is complete. So, if they hold back $700 for depreciation and the actual cost of work is a little more then they sent you, all you have to do is send them a letter of completion from your contractor with the exact amount when the work is done and they'll send you the difference.
And that's it; a new roof for the price of your deductible!