If your interested in municipal work, do some research on what municipalities you want to work for. More specifically, what contracts have been awarded recently, their specifications, their pricing structure, and what they are currently paying for work. At least around here all of that info is readily available on most municipality's websites, if you know what your looking for. Learn the differences between bids, and RFP's, and what is used most often in your area. Know prevailing wage rules, but realize some places they can be interpreted differently from city to city.
For example, we tend to bid contracts every three years, and do extensions on the first contract if the contractor is open to this. I price everything in 6 inch DBH classes for both pruning and removals, i.e. 6"-12" 13-18" ect up to 36", then a class for everything over 37". With this in mind it pays to know what the species composition and tree condition is of a certain municipality. We are not going to pay you more to trim a street of 35" Honeylocusts that havent been touched in 20 years, all over the power lines and houses, then a similar street full of 35" silver maples trimmed 6 years ago in a 30' wide grass strip, the unit price is as you bid it. Hopefully you can have a good working relationship with the city, so they will give you a heads up if its a really bad street and not take advantage of a super low bid price...but it happens.
Site conditions are important as well, most of the streets were I work are wide open parkways, not much overhead utilities in the parkway or houses close to the street. You get into an older municipality around here a lot of times all the overhead stuff is right under the street trees, and the trees are well over the houses on both sides of the street with on street parking as well.
Probably most important is network, get to know your local city arborist's, foresters, division supervisors ect. the better your relationship is with these people the more informed you will be about what work is available and what they are looking for.