Part of the question, you already answered that Certification is not the only criteria to become a better architecture or designer. You must have real architectural experience by designing some real world application.
I think, you can start by
1- Designing a component from ground 0 this may be in your current project, a module, a small application.
2- Thinking in terms of more efficient Algorithms, design procedure, patterns
3- Be in touch with latest technology, platform etc.
4- Learning more deployment patterns.
5- Learning more about data storage and retrieval systems.
6- Start participating in forums, Q&A sites like SO
7- Start writing small technical papers.
There are more points beyond the ones mentioned above, but these points are surely a starting point for the long journey to be an architect.
Plus, work under a senior architect / architect as a Technical Lead or Junior Architect will also act as a boost.
Finally, there are certain certifications by the industry leaders like Microsoft, IBM, and others. One of the certifications which I know is
MCA (Micorsoft Certiifed Architect)
But this certification has some predefined criterias like (Min 10 Yrs work ex etc..)