Just start out with a joint (and maybe a small hit - one or two) so you can control it somewhat.

When I first got high, it hit me after about 5-10 minutes and I felt like I was almost floating. I was walking around outside and it made me notice how sunny it actually was. I didn't get sick or anything like that. I just felt really silly. Like I had a permanent grin on my face that I just couldn't get rid of. I came down about an hour or two later. It was cool.