I would like to know what are the skills required for the SAP CRM - Functional Consultant ?? with sales and marketing experience can i write the SAP CRM Associate level certification exam directly ??
As suggested by Thomas, it would not be possible to pass CRM examination without undergoing proper training, preparation, reading the materials thoroughly and religiously. Your Marketing experience will only help you to understand SAP CRM, but it would really impossible task to pass without training and proper preparation for the examination. You also need to understand the SAP CRM functionality and its underlying business process in practical point of view.
Many people are even struggling to pass the exam even after proper training and preparation. Giving an attempt is not a big thing, but you need to look the amount of certification fee you are spending. Therefore, you should take easily, unless you are fully equipped to attempt.
All the best.
I don't think anyone would recommend that you go for a certification exam without dedicated study of the expected material, regardless of how much experience you have. The questions are specific and may not be related to things that you've seen day to day.
I recommend you find a good overview book or book on SAP CRM specifically to familiarize yourself with the functionality and business processes in CRM before you do anything else.
You can find links to books and websites with further information at SAP Career Blog Links under the Blogs for folks interested in Certification or just in learning SAP functionality section.
I hope this helps!