Hi
@Frimley111R
I don't want to teach 'your grandmother to suck eggs' as you are a marketing consultant....but the obvious answer is with market research.
Once they have established a demand for the product or service, at a price that is profitable for them and understand their competition (and how they market) and their customer base, then they can develop their brand position, marketing plan and identify tactics, budget and evaluation.
People should decide which marketing approaches and tactics to invest in (in your words 'what to try') by understanding their target customers, which communications and consumer channels they use, and what benefits are likely to appeal to them.
Small businesses either use the services of people like you, me and many others, who understand how to carry out market research and develop marketing and communications plans, get advice through business support organisations and/or read up on marketing content available on line.
More commonly, they often muddle through trying different channels without understanding whether they will reach/work for their target customers and whether they are identifying benefits their customers want. And without having an adequate budget to invest in their marketing.
How many hundreds have come on here and announced they have started up a business (because they enjoy doing something/don't like their job/have been made redundant), have zero/a tiny budget and want to market their services to the world

, have no money and therefore are going to use social media and online content.