If you're denied Social Security disability benefits the first time around, don't give up hope. Instead, request an appeal, and prepare.
The first layer of appeal after an initial denial is the reconsideration, where your state's Disability Determination Services (DDS) reviews your claim and makes a decision based on what's in your claim file.
At the reconsideration level, you don't need to point out specific errors made by DDS in its initial decision to be able to appeal. You just file a request for reconsideration with Social Security. You should, however, review your Notice of Denial and take note of which of your medical records DDS used in making its decision. Very often, DDS does not have all the medical evidence relevant to your case when making its initial determination. If anything is missing, submit it yourself to DDS.
You should also submit to DDS any documentation you have from recent medical visits. You have the best chance of winning your case if your claims file has pertinent, up-to-date medical evidence, including doctor's clinic notes, results of objective testing, and statements from your physicians.
If your doctor hasn't submitted an opinion (called a medical source statement) or an assessment of your residual functional capacity (RFC), ask him or her to do so. (If you hire a disability lawyer, the lawyer will have RFC forms to send to your doctor that will ask the information that Social Security needs to know for your medical condition.)
Also, check your original decision letter to see if DDS considered all of your medical conditions in making its decision.
If your claim is denied after reconsideration, you can appeal to an administrative law judge (ALJ) who hears Social Security disability cases. The ALJ will hold a formal hearing to ask you, and perhaps a vocational expert, questions about your medical conditions and your limitations. The ALJ who hears your case is not bound to follow any prior decisions made by DDS, nor will those decisions be given any deference. The ALJ's disability determination is completely separate from the DDS decision, and thus you aren't expected to point out errors or appeal particular mistakes made by DDS. You get a fresh chance to make your case in front of the ALJ.
You should request your case file from Social Security before your hearing date. (The hearing office must give you 75 days' notice before your hearing date.) Review the "technical rationale" for why Social Security denied you benefits. Be ready to explain why Social Security was wrong in denying you benefits for those reasons. You may need a disability lawyer's help to do this.
Make sure that the medical evidence in your file is updated before your ALJ hearing. A judge can't decide your case if you don't have medical records from the last 60-90 days before the hearing date.
When you receive the hearing date, request the most recent records from your doctor. You are required to submit this documentation at least five days before the hearing so the judge has a chance to read it. And if the technical rationale discussed certain medical records or tests, make sure those are in your file so that the judge can view them at your hearing. Having a disability lawyer help prepare for your appeal makes sense, since they know which records will be most helpful to your case. (Read more on using a disability lawyer at your hearing.)
You can also request letters from former employers, family members (especially those who help you with day-to-day activities), and friends.
For more information, read Nolo's article on appealing a denied disability claim. If you are denied benefits after your ALJ hearing, you might want to read Nolo's article on the mistakes ALJs make at Social Security hearings.