In addition to the above, you must have a clear idea of how efficiently you work or how long it takes you to complete a specific (chargeable) part of a job. You may consider a chargeable part of a job as an item or function. For example, a logo, a chat script, guestbook, script installation or etc. The more specific you are at determining a particular item and determining the amount of time you usually take to complete that item (from experience not guessing), the better you will become at setting more accurate quotes. It is a good practice to always add an amount of time to the duration it takes you to complete each item as a whole to allow time for revision and discovering bugs and etc. the amount of time you add is strictly a personal choice. I always add 1.5 hrs (none-chargeable hours) depending on the complexity of the task. After doing this for each item, simply sum up the duration and cost for each function/item the client requests.

If, for example, I usually take 2 hrs to complete a custom chat application and I want to be paid $ 15 / hour, the total duration will be 3.5 hours at $ 30.

Remember, a quote is simply tool provided to your client to know whether or not your services may or may not fit his/her budget or beats any potential competing service providers. That said, do list and separate all costs for base items from the options the client have requested while still displaying the total cost. For a designer / developer, mockup design and development related costs may be considered as base costs while chat rooms, member pages and shopping carts are options. The reason for separating costs into categories is to allow the client compare your prices with competitors much easier. A quote with a single total cost is fine for a client wanting only a simple website but when things get complicated with all the bells and whistles, you may turn a client off with an item with a long description section and a single total slapped at the end of the quote. Search the internet or use any invoices that you may have as a template to get a feel of how your quote should look like then enter your information accordingly. Whether your client has your email and number or not, always provide them at the end as well as a note suggesting that they contact you for further information. Be prepared to answer them.

When you are all done, think to yourself, "is this user-friendly?" If it is, you can be proud of yourself and continue with your newly found quote-making abilities!