Your best bet would probably be shopping your local agencies.
One concern that is raised a lot is CCC: care, custody, and control. Many general liability policies have an exclusion or clause for items under your "care, custody, or control". What that basically means is that if you cause damage to something you are directly working on, like the siding of a home, your insurance may not cover it if there is a ccc clause.
So when you go shopping for coverage, make sure to get a quote that includes their limit for CCC items. Under some carriers, it may get bundled with office or work equipment coverage. My policy has a $25k cap. I've seen some policies with much lower limits.
And if an agent says you don't need CCC, or that it doesn't apply to what you work on, ask them to put the explanation into writing.
I'm currently with JD Walters, but I'm going to be switching at the end of this year's contract, because they don't cover snow removal. I had a local agent iron things out so I will be keeping the same exact policy, only it'll be through their agency and with the added snow removal rider.
Apparently the policies that JDW writes are very specialized for our industry. It took quite a bit of doing just to get it transferred to another agent. So if you can deal with some of the limitations and negative feedback, JDW is worth a look if you can't find a good option locally.
Some factors that are probably working against you:
1. You're new in business
2. You have no business GL history
3. You're considered high-risk, for the above reasons.