Nikon D5000 Macro advice,

Hi, I am looking to get some top quality Macro shots with a D5000 I recently purchased,

The shots of the little frog in my pond are with a Raynox M-250 clipped to the standard 18-55 kit lens,

I am new to DSLRs & Macro so Can anyone advise or had experience of using the D5000 for Macro & what methods did you use?,
Many thanks, Jon.

(the first photo has what look like greenfly on the rock & the second gives some idear as to the size of the frog which is sat on the end of my finger)