Choose a program suitable for the job
If you have several programs available to you we have numbered the commonly used ones below in order of preference :-
      1.   Corel Draw, Quark Express, Pagemaker, Indesign, Freehand
      2.   Illustrator
      3.   Photoshop PSD
      4.   PagePlus, MS Publisher
      5.   MS Word
      6.   MS Powerpoint
Anything ranked lower than "2." can have severe limitations with certain types of job.
Programs ranked "4." have little or no colour management and struggle with multiple spot colours
Programs ranked "5." and below do not understand CMYK or spot colour and have no colour management capability.
If you intend to send final artwork as PDF or EPS rather than your native program files you can use whatever program you feel to be appropriate for the job you are doing. We can produce CMYK output for full colour jobs from any PDF or EPS file but if your job is to be printed using multiple spot colours (as opposed to a single spot colour) we recommend you use only programs ranked "1." or "2."

Prepare your layout
Before you start you need to consider the layout of your job and prepare your page to reflect this. Visualise the physical characteristics of the finished job and create a page in your program with this in mind. Place guides on your page where folds and creases will fall. Place further guides to show gutters and limit where your text can be placed. Remember to allow for bleeds.
Creating an actual size mock-up using paper, pencil and ruler can help with this.
We have created a number of ready made layout templates in commonly used programs for you to download  here.
More advice on layouts  here.

Create your artwork
Remember you are not only trying to create artwork that looks good but artwork that works when you send it away to be printed.
There is no getting away from the fact that in this sense producing good artwork involves a little more effort on your part. Taking some time to think about what you are doing and how we are going to use your finished artwork to produce your job virtually always pays in the end.
Create a separate folder for your job and copy all used files and graphics as you use them into this folder keeping everything together in one place
Remember bleeds.   Explanation..
Only use scans of a suitable resolution.   Scanning for Print..
Don't use fonts you don't have or that you can't send to us.   
Avoid making black text from multiple colours - it will look black but you'll get better, cleaner results using black ink only.
Try not to make small type out of colour tints.
More Information on text and font use   here..

Two types of Artwork
CMYK Full Colour and Single Colour:-
The easiest type of job for a novice to produce is CMYK full colour or single colour. Whatever you place on your page will normally print and when you check your (optional) online proof you will see exactly what you are going to get. You can even set up your system to view your online proof in a colour accurate environment.
Multiple Spot Colour Jobs :-
Inexperienced artists usually struggle with multi colour spot colour jobs. These are jobs that are to be printed using a separate plate for each pantone colour. The main thing you need to remember here is that anything on your page that is not in one of your chosen spot colours will not print. See our notes on spot colour.

Further information
Technically in depth artwork information is available from our Artwork Help Menu  here.
Many issues are handled at various skill levels with information useful for both novice users and experienced, professional graphic artists.