If you are responsible for selling "consulting", it's important to recognize that you can be a vendor of consulting or you can consultatively sell consulting services. That's quite a mouthful.
If you are in a service provider (consultant) role, you may or may not be directly responsible for selling products or services. However, you will likely be persuading someone to a point of view or to buy in to an idea or approach. Consequently, it's helpful to be attentive to the principles of consultative selling.
Selling is Other Centered
Your focus should not be on features and functionality of products and services. Instead, you should focus to constantly re-evaluate a customer's business operations in order to find ways to increase their profits or other key performance measures. Specific products and services are tools that may play a role in a supporting client objectives.
Diagnosis Before Prescription
As a consultant, you should defer judgment and conclusions until some consideration of related issues and options has been made. It's a double-edged sword: Because you are an expert, you will often recognize, long before the client does, what they might need. The temptation to prematurely present is both unprofessionally risky and could reinforce the image of being a product-peddler.
Focus on Value, Not Price
You shouldn't aim to come in with the best features for the lowest cost. Instead, aim to help your customer bring their services to market with better competitive capabilities, and/or a lower cost. If you can help your customer save more money, make more money, increase competitive advantage, eliminate risk, increase the return on investment; you are a partner to their success, not a vendor. Ideally, they learn that they can't afford to do business without you.