You can search using a specific body, or by using a specific missing person.
To search by person, I'll go to CharleyProject, NAMPN, DoeNetwork etc. and open up one of their case files. I'll input the person's information into IdentifyUs: their approximate height (I usually do +/-3 inches), age, sex, race and any tattoos they have. I'll usually add the person's year of disappearance (and maybe the next two years) in ''Probable year of death'' and it will rule out UIDs that don't fit that time of death.
To search by body, I'll go to DoeNetwork's unidentified list or to this very forum and open up one of the pages. Then go to NamUs's findthemissing site, input the UID's information and go through each missing person that matches that description. I'll pick out the ones I think are most likely and post them here on the forum.
I usually don't input hair or eye color because, if I'm searching by person, NamUs will rule out skeletonized bodies that don't have that information available. And keep in mind that, sometimes, few parts of a body are found and investigators can't determine important things like race, height, age or even sex. So you'll have to look for skulls, femurs etc. whose little information matches up with your missing person.
By the way, if the missing person and UID's pages in NamUs both say ''Samples submitted - tests complete'' under DNA, it's not a match. NamUs automatically scans their DNA database for matches once every week or two and, if there is a match, the authorities are notified and both pages will be taken off NamUs soon.
If you find a potential match, you can start a thread. Or, if there's already a thread for a particular UID, you can post your potential match there. Don't put your potential match's name in your thread title, though.
This is the order titles are usually in: State - city(or county) - race/sex - case # - age - (any distinctive features) - date
For example, take this guy:
https://identifyus.org/en/cases/11214
He's a white male between the ages of 20 - 30 and he was found on 4-11-2013 in the city of Pharr, Texas. His NamUs case number is UP11214 and he was found wearing a purple cloth bracelet with ''Jesus Cuida de Mi'' on it.
So, his thread title would be like this: ''TX, Pharr, WhtMale UP11214, 20-30, ''Jesus Cuida de Mi'' bracelet, Apr'13''
Then I'd just post the NamUs information and any sketches/pictures in the OP. And make a second post for any potential matches I have.
And here are some random pointers:
1. Use Google Maps and/or Google Earth. It's very useful and tells you how far away the missing person and UID are, if there's a highway or anything that would make it easy to dump a body, etc.
2. Remember that the 'date last seen' might not necessarily be correct. Sometimes the person filling in the information might accidentally put the 'date last seen' as the day the missing persons report was filed or the day the case was put into NamUs.
3. If the missing person is a runaway, try to find any social media accounts they have and see if they have been posting on them. It can really help you rule the person out when it comes to identifying a body.
4. Don't rely too much on facial reconstructions. They can range from uncannily accurate to ridiculously inaccurate. They're really just an estimation that gives you an idea on what the person MIGHT have looked like.
Hope that helps. Just ask if you have any more questions. : )