When you have your business line of credit, be sure to make any payments early and, if possible, to pay down any debts or loans in full.
For example, say that you have a business credit card and take out $5,000 in office supplies for a new office space you are renting from a commercial landlord. After making your purchases, try to pay down the entire $5,000 balance before the end of the billing cycle.
This shows the credit card holder that you are very trustworthy when it comes to credit, and this will significantly bump up your business credit score.
Loans work the same way. If you pay them down aggressively, such as by making more than the minimum payment and paying down the full loan balance before the term ends, your credit score will increase more than if you just made a minimum payment. Another reason not to make minimum payments is that you'll cost yourself more money in the long run through interest accrual.