Managing your client’s expectations is critical to being a successful SEO consultant – or any kind of consultant for that matter. If the client has completely unrealistic expectations for you, any SEO efforts that you undertake will be seen as unsuccessful regardless of whether or not you actually are successful.
Making sure that you and the client are on the same page begins even before any contracts are signed. You should be evaluating how reasonable and realistic a client is from your first interaction. Do they seem to think SEO is going to be a really quick project or think they are doing you a favor by giving you business? If so, you probably want to move on and recommend someone else that might be able to “better” help them. Stay away from people who think they are helping you out by giving you business. These people typically think that since you are working on the internet and the internet is fast, SEO will be a fast and cheap process. Usually they think SEO is somehow magic too. Run away.