You can provide all the services which you have mentioned above even before qualifying CS.
General Rule : Anybody can provide any service under the veil of Business Consultancy Services except Statutory Audits, Secretarial, Cost Audits and other legal compliance to be provided by only such specified professionals.
So, Simply, incorporate a Private Company for the Business Consultancy. Always prefer creating a Company than a Partnership Firm/ LLP as "Pvt. ltd." gives an impression of Trust, Competence, Sustainability.
Also, Create a website. Use Google Ad Sense and Social Media to market your services.
Target Tech Startups also, as your Niche area.