What are the main points that I need to keep in my mind while writing my CV or resume to make it more impressive?

First of all, customize the resume to fit every job you're applying to. Have you done that? If you haven't make sure to have different resumes for every job you want to get. Then, it's important for you to be very organized, make sure the lenght of it is the right one, ideally 1 page. Stay truthful, don't make up any jobs or exaggerate with information to make it more impressive. I would definitely recommend that you focus your energy into writing about your skills and abilities for THE job; don't add information that is not relevant. Make sure it has plenty of keywords, it'll improve the chances of you being considered, and include your achievements, saying "improved ..." or "increased", obviously make sure your grammar is perfect and there are no typos or mispelled words. I'd recommend for you to find help with Job2grow, they've got plenty of useful tips for this specific subject, resumes.

keep the information factual and objective so that the covering letter can address the wants of the employer with benefits as shown on cv/resume.

be honest

list everything

spell everything right

have good resources

Thanks for your suggestions, friends. This really helps a lot.