A few quick tips….
Don’t try to cold approach people you don’t know. Instead, select a niche and build a reputation amongst the people in it. Plant roots, show up, be helpful, publish content and build your reputation. Gradually network your way to the people you need to connect with. It takes time, but it works.
Create templates of all the major docs you use. Don’t recreate every doc for every project. Make sure you have templates of your kickoff call, contracts, proposals, and well-designed templates of common deliverables.
Don’t take sides in internal conflicts. Listen to what people are saying (the information is useful), but don’t express an opinion on who’s right or wrong unless you want to be drawn into the conflict.
If you want stakeholders to support you, don’t surprise them. If you don’t engage stakeholders during the process of the project, don’t be surprised if they don’t support your recommendations at the end of the project.
Put the invoice dates in your calendar. Once you know when invoices are due, list them in your calendar and make sure you always invoice promptly and on time. Check the invoice carefully for errors because (trust me), invoice errors can be embarrassing to explain.
I hope you get as much mileage out of these as I have.
Not taking sides is super-hard to do, especially if it's a long-standing relationship: internal conflicts are everywhere and as an external consultant you are prone to some degree of venting just because you are "from outside".
In some situations it seemed to me that internal conflicts is how some people spend their entire days at work: they try, sometimes not consciously, to drag you on this or that side of an argument and, while intellectually you know you shouldn't do it, you also know you might appear as less likeable by not taking sides.
I usually repeat myself "Is this true? How do I know this is true?" or "There's another side to this" mantras to avoid the taking-side trap.