At the moment, I don’t know you, your business, your website, your resources, your competition or your product. Even with all that knowledge, calculating ROI is extremely difficult because ultimately Google decides on who ranks where in its results – sometimes that’s ranking better sites, and sometimes (often) it is ranking sites breaking the rules above yours.
Both require knowing your audience. To succeed at both strategies, you must have a good understanding of your audience and how they act. By using buyer personas and psychographic segmentation, you can get to know your audience, discover what their needs are, and what they are searching for. Then you can create valuable content that shows up when they go looking for solutions related to your brand.
Determine who your main online competitors are. Research how they work, how they market and how big of a market share you believe they have. Sign up for e-newsletters, research their press releases and determine the strengths and weaknesses of each online competitor. You may even need to purchase something from them in order to understand how they complete their sales process.
Think about how Google can algorithmically and manually determine the commercial intent of your website – think about the signals that differentiate a real small business website from a website created JUST to send visitors to another website with affiliate links, on every page, for instance; or adverts on your site, above the fold, etc, can be a clear indicator of a webmaster’s particular commercial intent – hence why Google has a Top Heavy Algorithm.
Redirecting is the act of sending a user to a different URL than the one initially requested. There are many good reasons to redirect from one URL to another, for example, when a website moves to a new address. However, some redirects are designed to deceive search engines and users. These are a very poor user experience, and users may feel tricked or confused. We will call these “sneaky redirects.” Sneaky redirects are deceptive and should be rated Lowest.
Ask for a technical and search audit for your site to learn what they think needs to be done, why, and what the expected outcome should be. You'll probably have to pay for this. You will probably have to give them read-only access to your site on Search Console. (At this stage, don't grant them write access.) Your prospective SEO should be able to give you realistic estimates of improvement, and an estimate of the work involved. If they guarantee you that their changes will give you first place in search results, find someone else.