Hi Paulette
I suggest that you have your tan the day before you are due to go on your holiday and that you exfoliate & do any hair removal the day before your tan. Good preparation will make your tan wear better as will a good moisturising routine following the time you shower off the initial colourguide.
There are many tans on the market, some are really natural looking and wear off really well others can be more fake looking and not all will have such good fade off qualities. Make sure your therapist is properly trained and selects a solution which is suited to your skin type.
If you want any other info, please feel free to ask, although I am sure you will get a lot of help from the geeks on here.
Have a great holiday!
Kind regards
Mandy