There are several methods for qPCR analysis of miRNAs, and both precursor and mature miRNAs can be analyzed. There are a large number of published reports on such analysis. Go through the methods and finalize the best one for your experimental design
The precursor miRNA qPCR analysis is similar to analysis of specific mRNAs. You need to download the precursor sequences, identify good regions for primer designing (include secondary structure analysis at this step), check primer specificity in Primer-Blast, and rest is same as regular qRT-PCR analysis of genes/mRNAs. There are plenty of published articles. see 1-2 links given below
Article Real-time PCR quantification of precursor and mature microRNA
Article qPCR-based methods for expression analysis of miRNAs
I hope these will be good to go through, you may refer to some more