I always had this problem with sales, when I started few years ago my competitive advantage was the price, I was charging very low, like ridiculously low, that worked for that time but now with more experience and responsibilities I charge around 3x a full-time employee hourly rate so it become challenging to close more deals.
It's not about price, or even about sales. You are struggling to close because you are not communicating sufficient VALUE. People buy value, not features or experience. Work on your marketing messages. Be clear about the personal benefits, the dramatic difference, and the reason to believe in the services offered. These are the three elements of persuasion that shape a buyer's decision.
Most people find the reason to believe very easy. The dramatic difference isn't 20% different than the other options, it needs to be 50% different to get people to switch behavior. Focus on the motivation and PERSONAL benefit to the target customer (not target company, people are customers not companies). How does their life improve choosing your service? That's what will close more deals (provided you're a match in the first place).
The top-3 reasons people in business will consider buying anything, is to:
1. Save them time, and/or
2. Save them money, and/or
3. Make them money (best if hitting all three).
Not sure which of those you're offering, but #3 has the greatest chance of success. Especially if you can convey 'how much'.
If you can tell a potential client that you can make them $x more in gross profit, there ears will perk up.
The challenge for you, is in having the confidence, skillset and determination to actually make it happen for them. The larger the amount you state, will acquire more interest such that you don't have to worry about price.
As an example, if you can tell someone they will make an extra $100,000 above and beyond what they normally make ... you can set your own price as far as fees.
You have to look at it, as if you won't get paid a penny unless they reach your stated objective. Now, the onus is on you (which is where potential clients believe it is NOT ... thus they don't often hire consultants).
Consulting goes from "a guy" to "that guy" to "the guy". As you make that transition, you need to develop your personal branding and get more referencable customers who can vouch for you.