There’s no simple answer to this. Optimising your site for search engines is how to get to the top, but the process that’s needed to get there can vary. It’s something we specialise in at EthicallyMAD, so drop us a line to chat and we will take a look at what might be needed in your case.
(This is something that takes a long time to train in with many variables, so it is rarely something we suggest people do themselves. One thing you can do to help though, is to create plenty of regular content - ideally articles of 1-2,000 words.)