If you are talking Active Duty or Reserve, I can help. I've seen packets across all branches. Familar with boards too.
Your file should be very good..reviewed by several people to assure you don't have mistakes in your grammar, appearance, and letters of recommendation. Get your photo within one month of submitting your packet, I don't care what the regulation says. Despite experience most applicants have, sometimes even SFCs have weak packets since their LORs were weak, indicating either the interviewer does not really want this person on the WO Corps or the candidate wasn't really interviewed.
Keep in mind not all letters of recommendations are created equal. I've seen more than a few CW5s who wrote LORs which were way too long and lacked any real substance other than 'this is an extremely hard worker'. You can't control what someone writes, so make sure you find the right person who is familiar with the process. Lower density MOSs don't do these as often as the Command Chief Warrant Officer of an Aviation Brigade. Rank in these cases matter. LORs from a few CPTs who have 3-6 years of experience don't compare as well to those in the board who have 10-20 years experience to compare folks to.
All that said, if the packet is great, but NCOERs are weak, there is really not a great chance to get picked up unless the branch is really short WOs and does not have a good feeder MOS to populate the ranks. If you are NG, just disregard this whole post, but figured someone here could use the info.
Good luck.