Amps are a fairly soft tipped plant, so cuttings need atleast 4-6leaves from the growth tip to strick, cut on a 45 degree angle, the leave it in either pure soggy spag, moist perlite or in straight water, you will need a constant high humidity and temps of 25-30c.
don't use rooting homone as many lowlanders dislike it and preffer water, neps have natural root stimulating hormone and powders and gels can counter these, however in saying this I find many intermediate hybrids preffer added hormones.
Basal rosetts are the easiest to take and in some cases will form their own roots and make a new plant by themself, also like amny lowlanders (expecially mirabilis) they will focus on leaf and trap growth before roots, I have had mirabilis form several traps and leaves before even thinking of making roots.
I find seed is a good way to propogate amps, I have recieced both seed and small 1-3cm plants and they reach a 10-15cm diameter in a matter of 11-14months when grown in lowland conditions year round.
Hope this helps.