It is best to wait until you are incorporated as a nonprofit in your state and have your letter of nonprofit status as a 501(c)(3) from the IRS before you try to raise money through contributions. Incorporation will protect your personal assets in case you are later sued. Before incorporation you are personally responsible for how you handle donated money. Also, you cannot tell donors that their contributions are tax-deductible until you are officially declared a tax-exempt nonprofit by the IRS.
If you need to start raising funds before you are incorporated and officially designated a nonprofit by the IRS, you might want to consider a fiscal sponsor that can receive contributions for you. A fiscal sponsor is simply another nonprofit that is willing to handle your donations for you.
Are you planning to not seek incorporation? Check out the pros and cons of becoming an unincorporated association.
For more information, see Can a Charity Raise Funds Before It Receives 501c3 Status?