There are various considerations for accepting an application, covered in the guidebook (PDF). Part of the process will involve the application going through several panels, including:
String Similarity Panel – assesses whether a proposed gTLD string is likely to result in user confusion due to similarity with any reserved name, any existing TLD, any requested IDN ccTLD, or any new gTLD string applied for in the current application round. This occurs during the String Similarity review in Initial Evaluation. The panel may also review IDN tables submitted by applicants as part of its work.
DNS Stability Panel – reviews each applied-for string to determine whether the proposed string might adversely affect the security or stability of the DNS. This occurs during the DNS Stability String Review in Initial Evaluation.
Geographical Names Panel – reviews each application to determine whether the applied-for gTLD represents a geographic name, as defined in the Applicant Guidebook. In the event that the string represents a geographic name and requires government support, the panel will review and verify that the documentation provided with the application is from the relevant governments or public authorities and is authentic.
Technical Evaluation Panel – reviews the technical components of each application against the criteria in the Applicant Guidebook, along with proposed registry operations, in order to determine whether the applicant is technically and operationally capable of operating a gTLD registry as proposed in the application. This occurs during the Technical/Operational Reviews in Initial Evaluation, and may also occur in Extended Evaluation if necessary and if elected by the applicant.
Financial Evaluation Panel – reviews each application against the relevant business, financial and organizational criteria contained in the Applicant Guidebook, to determine whether the applicant is financially capable of maintaining a gTLD registry as proposed in the application. This occurs during the Financial Review in Initial Evaluation, and may also occur in Extended Evaluation if necessary and if elected by the applicant.
Registry Services Panel – reviews the proposed registry services in the application to determine if any registry services pose a risk of a meaningful adverse impact on security or stability. This occurs, if applicable, during the Extended Evaluation period.
Anyone can register a TLD, though you'd better own the trademark, and others can file objections to your TLD application. Also, you'll have to be able to operate as a registry.
The costs start at $185,000. From the FAQ to which you linked:
- 7.2 How much is the evaluation fee?
The evaluation fee is estimated at US$185,000. Applicants will be required to pay a US$5,000 deposit fee per application request slot when registering. The US$5,000 will be credited against the evaluation fee. Other fees may apply depending on the specific application path. See the section 1.5 of the Applicant Guidebook for details about the methods of payment, additional fees and refund schedules.
- 7.3 Are there any additional costs I should be aware of in applying for a new gTLD?
Yes. Applicants may be required to pay additional fees in certain cases where specialized process steps are applicable, and should expect to account for their own business start up costs. See Section 1.5.2 of the Applicant Guidebook.
- 7.5 Are there any ongoing fees once a gTLD is approved by ICANN?
Yes. Once an application has successfully passed all the evaluation steps, the applicant is required to sign a New gTLD Agreement (also called Registry Agreement) with ICANN. Under the agreement, there are two fees: (a) a fixed fee of US$6,250 per calendar quarter; (b) and a transaction fee of US$0.25. The latter does not apply until and unless more than 50,000 domain names are registered in the gTLD.