Build your services and niche:

What type of marketing services are you going to offer? Who is your intended audience? You may begin establishing your expertise in your sector after you are aware of what you excel at and who you want to serve.

know the importance  of  identify your audience 

Developing a powerful brand:

What sets you apart from the competition is your brand. Make sure your branding is consistent across all platforms, including your website and social media accounts.

Make the appropriate hires:

Your most precious asset is your staff. Make sure the people you choose for your team are talented, driven, and compatible with your company’s culture.

delivering top-notch client service:

Your lifeline is your clients. Aim to exceed their expectations and go above and beyond to suit their needs.

Stay up-to-date with the latest trends:

The marketing landscape is constantly changing. Make sure you stay ahead of the curve by reading industry publications, attending conferences, and taking continuing education courses.
Invest in technology.

There are a number of marketing techniques:

 help you automate tasks, improve efficiency, and track results. Don’t be afraid to invest in the right tools for your business.

Be patient and persistent:

 Building a successful agency takes time and effort. Don’t get discouraged if you don’t see results overnight. Just keep working hard and stay focused on your goals.

Here are some more tips I came up with:

Create a business plan. This will help you map out your goals and strategies for the future.
Set realistic expectations. Don’t expect to become successful overnight. It takes time to build a successful business.
Be willing to take risks. If you want to be successful, you have to be willing to take risks. Don’t be afraid to try new things and experiment.

Here are some articles that can answer some questions that might interest you:

how to builds your brand ? 

the importance of questionnaires in research marketing 

how to builds an effective market strategy ?