Amateur fiction is not the only situation where one will want to create some fictional pseudo-science, but ok, it's the main one. But why you would do it doesn't matter, the problem remains, some errors get done over and over, and avoiding them would save nerdier readers a lot of cringing.1- Too much science.
You're making up a world where the dead walk, identify humans, overpower and eat them. And they're also contagious. Oh, and also it's a virus, a not really alive parasite that needs to be coddled by a host cell to show any form of activity, yet it thrives in a dead host. Also it can infect a person, turn it, then have that person infect someone else in twenty minutes despite the fact that no virus can be replicated this fast simply because human cells can't work this fast. And don't forget that despite having lost the ability to produce new energy, eliminate waste or maintain tissue, the zombies survive long enough to besiege the last humans until they starve.
HOW DO YOU EXPLAIN IT???
The answer is you don't. Oh, there is plenty you can explain and it can be interesting, as long as you accept that there'll be holes. But if you attempt to cover every part that doesn't quite agree with reality, you'll just create more holes, lenghten your technobabble parts and eventually outright contradict science. Trust your readers' suspension of disbelief, they already expect your story to be imaginary.
Image: Trying to explain away the holes in the explanation of the holes in the explanation of the holes in...... or This Is Your Brain On Technobabble.2- Binomial nomenclature
Zombies are not a species. Naming them like a species would be like naming a butterfly and its caterpillar as two different species. If scientists are going to name something, it's going to be the virus or the disease.2-a- Latin is mandatory
If you do want to name the zombie virus, note that because viruses are only being studied and named for a relatively short time, many have non-latin names already. For the sake of example, lets say the zombie virus came from a mutated rabies virus; then Lyssavirus zombie
would be a perfectly suitable binomial name. So for the love of all that is good and holy, unless you actually know Latin, do not rape Latin in vain. Don't hesitate to ask Wikipedia for the genus name of whatever virus you want your bug to be close to. Or make up your own, about anything goes - except fake Latin!3- Super fast science
Scientists will not figure out everything about zombies, the virus or anything related in a couple of days. The smartest scientists with the fastest computers still can't provide information without the data to work with, and in the field of biology everything takes time. A virus under a microscope does nothing, figuring out how it works involves observing patients, infecting animals and cell lines, compiling stastistics on its spreading, etc. Determining how though it is involves exposing it to the usual disinfecting agents and then see if it'll still grow if introduced into a cell culture. Determining if it's sensitive to antivirals means testing in both cell lines, animals and humans, and often what works in one doesn't in the other. Every bit of a virus's behaviour depends on its host cell, and those are not always cooperating; they're needy and slow.
If in your zombie infested world, you want a wealth of details to be known about the zombie virus, make the epidemic slow, or have small scale outbreaks happen a couple of years before the big one. If an african village gets destroyed, it would provide science with usable data and samples while being just one notch above conspiracy theory in the public eye.
Ok, this is all I could think of for now, other forumites are welcome to add their own pseudo-science pet-peeves and how they think it could be helped.