At first it depends in which countries is your market, i.e. in which countries you are planning to start your business.
You may start patent search in random patent databases to get some preliminary overview about possible relevant patent documents, but finally you need to analyze the legal and geographic protection coverage and statuses of critical patents in respect of those countries where you are planning to do your business (e.g. production, selling, etc.).
For that kind of patent search like freedom to operate, Google Patents may not be very good because the coverage of countries is relatively small, the search features are not very good and the content of Google Patents is not up to date.
Whatever of free patent search tools or databases you use (Google Patents, The Lens, Espacenet, Patentscope, Depatisnet, PatentInspiration, etc), before detailed analysis and any decisions you always need to check national patent databases and registers also. Only national patent registers can give you most up to date and correct information.
When the possible critical and valid patents in relevant countries has been detected, then claim analysis and comparing with your products starts.
At the same time you need to continue monitoring publications of new patent applications.
But these are just few aspects to consider. To start, the best thing is to consult with patent attorney.