Setting Default Value in Drop Down List

Hi all,
Have a quick question here:

I have a drop down list.
How can i set the first selection as a default.
For example: my options are 1,2,3. How could I set it to first display "Please select one" to show up in the list first (ie not a blank field display before the option).

You can't change the blank option display. The only way to do what you're wanting is to add a new option to the field then set the registration default to the value of the new option, but this will only apply to registration. To prevent selection of the empty option set the field to required.

Thanks and have tried but unable to do so.

This particular field is created in separate tab, which is only Published for a certain period.
I just need the selection to default be selected as "Please select one".

The field settings are as follows:
Pre-filled default value at registration only: Please select one
Required?: Yes
Show on Profile?:No
Display field title in Profile?:
Searchable in users-lists?: No
User Read Only?: No
Show at Registration?: No
Published: Yes
Size:0

values:
Please select one
Cheque
Online Credit Card
Bank Transfer / Internet Banking

What else am I missing?

If the user has no value stored it'll add a blank and have it pre-selected. There's no way to avoid this behavior without developing a custom select field. I suppose one option is to create a custom database table with the options you want then use CB Query Field and its Query Select fieldtype to build its options from that table.