Welcome to Wee Ghosties! I'm Stacey, I've been investigating the spookier side of "life" for nearly 20 years and have picked up a load of tips. I'm happy to answer questions, please write me at infoATweeghosties.com! Please replace AT with @ -- eh, you know the drill...
Getting started in ghost hunting is as simple as walking outside with a notepad and pencil. The only real requirements are the ability to do research, a healthy dose of common sense so you're not chasing wild geese and an open mind. There are some in this field that believe anything that seems even half-way plausible has to be spirit activity, please don't confuse a raccoon under a house with a ghost (it's happened before and will happen again)!
You do not need a certificate to start investigating ghosts or buy a bunch of equipment, I still use primarily paper, pen, a watch and a tape recorder. The rest just helps you to pinpoint activity but it's not necessary. Trust your instincts and use them to help you find what you're looking for, you don't need a $100 thermometer to tell you it got colder in one area of the room than another. ;)
Ok, let's get busy.