I am thinking to submit my paper in IEEE letter. I want to know to know what are the things I should to keep in mind before submitting in IEEE letter so that the chances of Acceptance will be high.
the trivia first: the work should be new, not previously published elsewhere and have a useful background. The closer it is related to help solving todays challenges, the better.
IEEE provides a rather restrictive template that should be used to submit the work in first place. At best, have LaTex used to create the paper and make sure that you get a thorough review on language before submitting.
Even the best technical content could be rejected if the language is poor in vocabulary and grammar.
Include graphics in highest possible resolution - poor graphics can easily ruin a first impression of submitted paper.
Yes - everything mentioned in the first replies is important.
However, I think, one thing was forgotten: You should clearly describe the "state of the art" that means: All papers which have been earlier published dealing with the subject of your paper must be listed/referenced. And you should explain if and why your paper fits into these existing papers (with new or alternative results).
Few things like Plagiarism need to be checked before submitting a paper, the paper should reflect the exact sound knowledge you possess, the literature should be mentioned clearly like from where you took that material and why and what you understood from that. And most importantly you need to go through the article before send the paper to the journal.