Local SEO is not a one-off project. It requires ongoing attention. Set up Google Search Console and Google Analytics to monitor which keywords bring traffic, which pages perform best and where people drop off.
Review your local SEO performance monthly. Look at your map pack rankings, organic traffic from Manchester postcodes and conversion rates. If something is not working, adjust it. If a competitor overtakes you, find out why.
The businesses that win at local SEO in Manchester are the ones that treat it as an ongoing investment, not a box-ticking exercise.