I agree with PencilMeIn. Just grab a brush and go. I did a little research to see some techniques and some other artists' work but it really just depends on what you do with it.
I finished painting a saw blade recently for a friend that took me forever (really-almost two years) to finish. I started in oils and didn't like them at all. So one day I stripped the paint and restarted in acrylics. I had it done in about two weeks.
I'm not much of a painter but acrylics are my choice.
Good luck-look forward to seeing your work.
I always use acrylic (tried oil for a few years but switched once i got the hang of acrylis again). Dont be afraid to layer! Sometimes the paint dries too quickly to get much detail in but if you mess up you can always paint right over it (not like oil, which takes a lifetime to dry! ugh) All you really need is paint, a palet, canvas & brushes. You can also water it down if you're having troubles with small details, clouds or grass, etc.
i prefer acrylics , you can go as thin or as thick as you like and you dont have to wait for it to dry, i paint thinly in layers starting from dark to light colours and finish with the highlights. just experiment and you will start to pick up your own way that you prfer.
It depends on what my crazy artists brain does that day.
If I want a highly detailed piece, then I use oils. If I'm in a rush, then I use my Acrylics. You can purchase extender and Matt Medium to thin and extend drying time with the Acrylics. Purchase a few instructional books, they come in handy to practice techniques until you develope your own. The books also have handy tips and suggestions that come in very usefull when you first get started.
It all depends on you, what you feel like. Purchase a starter set of each medium, try using different techniques to get a feel for it.
You can do so many types of painting with acrylics - like kcortese mentioned, they have the mediums so you can make them behave like other types of paint such as oils. You can even thin them to watercolor - although you can't lift them back out like you can real watercolors.
There are some good books out like "Acrylic Revolution" and "The New Acrylics" that give a creative look at the potential of acrylics.
I always just think of something cool and go with it. I usually draw it with pencil on the canvas first and then paint it but not always. My paintings hardly ever turn out as I first imagine them to be. It's amazing how they come to life on their own sometimes.