For English we use syllables to write, read and pronounce each of our words as well as quickly pick apart any new words(like, say, the newly minted dictionary entry Bromance) or dialects we encounter. By comparison, Japanese pronunciation is much different, and instead of saying their syllables altogether in a constant breath, each one is said distinctly as a mora, or a unit of sound that helps us decide what gets emphasis in the words we say.
Take the word Mora, for example. Instead of pronouncing it as we might've learned from American style English(All a bit slurred together, IE MOR-a), we give each part of the world a bit of heft, pronouncing it a bit more like this (MOH-rah). Think along the lines of the way British English and Spanish is spoken, especially the Spanish rolled R's and you'll get even closer to Japanese style pronunciation.
Side note: Pronouncing Japanese through American style English accent is known in Japan as the 'Gaijin-san' accent, the term loosely translating as 'Mr Foreigner", and often communicates that your main knowledge of Japanese is through the heavily distorted versions seen in pop culture(such as in Banzai & The Karate Kid, no disrespect meant to those who do Wax On & Wax Off). It's viewed much the same way we'd view Japanese people pronouncing English through their accent, and I would assume is NOT something you'd like to be associated with.
For a quick breakdown on(something close to) proper pronouncing:
a = as in father
i = as in eat
u = as in food or zoo
e = as in end
o = as in Ohio
Now that we have that down, let's take an English word and show how the pronunciation would break down in a Japanese accent:
When pronouncing Japanese words, always, always, ALWAYS remember to keep this in mind and to say each Mora with the proper stress and rendering. A change in stress could give you an entirely new meaning or new word, such as with shojo, which can mean either young girl, virgin or heavy drinker(among other things) depending on how you stress each Mora, as well as situational context. One way to better develop this is hearing native speakers and taking note of how they say each word, among other uses and intricacies I will discuss later on
A more elaborate explanation can be found here and the vowels can be heard here, if you're interested. If like your knowledge with a bit more nerd flavor, point your browser here, to Danny Choo's Mirai Suenaga pronouncing each of the basic sounds