I've consulted for home improvement companies before and there are a few things to consider:
1. The more defined the scope of your need the more effective we can be. Otherwise you'll pay me for the time it takes to figure out where my time is best utilized. Think "I want a sales methodology to assist my sales team in transitioning from EDDM, home show, and referral leads to canvass leads" as opposed to "I want a program to help my sales guys close more"
2. Consider your ROI. Discuss how much more revenue you can generate vs the investment. I know a company that invested over $1M in a sales consultant. They would have to see an increase in sales of $10M to recoup that. ..good luck.
3. Does the consultant have a background and successful track record in that area. The aforementioned company was a canvassing window company. The consultant never sold a window in his life let alone a canvass lead...hence the problem.
4. How will the consultant be utilized? You said marketing. WAY broad. Creating a marketing strategy? Creating a campaign? Collateral? Making the connections for you? Block time? On call?
5. How will the consultants help impact other areas of your business? Example just this month a guy says, "I want a canvassing program: Ads, job descriptions, comp plans, training modules, performance tracking, etc. I'll roll it out myself." "No problem....can you handle the data coming in?" "Yeah. I just need a system." Guy calls back. "You were right. We've got to many contacts coming in...I need a call center"...okay. BAM! Guy calls back. "My guys are struggling with canvass leads. Can you train them?" My point is that a small investment can turn into a headache if you don't anticipate the ripple effect or take a question your guy asks you seriously.
6. Be ready to hear things you don't want to hear. I'm not there to be your friend or agree with you. I'm there to help you reach whatever goal you have and sometimes you won't want to hear the truth.