The Federal Government does not issue small business grants.
So searching through their great database at Grants.
gov is not going to help you.
Despite what many television commercials or spammy websites try to tell you, you will not find Government grants for starting a business or for covering your day to day business expenses.
There is of course funding out there for small businesses but finding it can be tricky at best.
Here are some tips to help you with your quest.

• For government funding look to state and local government agencies as some Federal funds do make their way down the chain and end up with economic development departments.
  What grants are available will be dependent on the state where you live so the best place to look for them is on the website for your state or city government.
  
• An online resource to help with Government and privately funded grants is the Small Business Loans & Grants Search tool at search.
  business.
  gov/startLoans.
  html.
  You enter your criteria including what sort of business you have and what you need funds for and it will give you some funding options.
  
• The Small Business Association (SBA) is a great resource for everything to do with small businesses, although they can only help directly with small business loans rather than grants.
  Their website has heaps of information but your local office may be worth a visit to see if they have heard of any local grants that you may be eligible for.
  
• The internet is always a good research tool, but in this particular arena you will have to work to sift out the spam sites that are trying to sell you some form of information that is already publicly available.
  Try local searches for more relevant information.
  
• Quiz your local business advisors such as your bank manager or your accountant as they will have contact with a lot of other small businesses who may have secured grant funding from somewhere.
  
• Keep an eye on your local business newspapers and magazines.
  Private fund givers may be interviewed in such publications along with other businessmen who have secured grants.
  
• Join your local business group and network with other members to see if they have found any grant sources.
  The group itself may also provide grants to members.
  

Talking with others and constantly being on the look out for grant opportunities is the best way to track them down rather than deciding that you will spend next Thursday say on this task.
Grants will come to your attention at the oddest of times, perhaps having coffee with your friends or family, perhaps when reading a trade magazine.
Stay aware and you will find your funding.