Budget funds to cover professional association meetings and workshops you may attend. Also, if you anticipate having clients in another geographic area, you may need to pay your travel expenses to meet with them. You can certainly negotiate with them to cover those expenses, but they may chose to reimburse you rather than paying for them up front.
When out on business, be professional and gracious. If you are meeting a client over a meal, pick up the tab. You can write it off as a business expenses when you file your taxes. However, don't be unnecessarily lavish entertaining clients. People will worry that you are overcharging them to pay for your extravagant lifestyle.