the more you do it the more you tend to be able to bring back, imo
i would get into meditation and yoga. try and enter hyperspace with the most calm and coherent a 'waveform' of consciousness as you can. think of you're consciousness like the waves on a pond. the more calm and coherent it is, the more organized our focus and memory will be..as opposed to them being choppy and dissonant. meditation has been shown to have all sorts of amazing benefits for memory and focus, and even thickens the brain in certain areas and builds new connections
there are a lot of ways though really. I've found that just smoking changa in lower end doses during meditation/yoga over the period of an hour or two, and just exploring my memory of trips, can really open up my access to my memories of past experiences
another way is to record yourself so you can just start talking immediately once you start coming down..or write things down if you want. this can help over time but only so much
one way, for the longer trips at least (lsd,aya, etc) is to repeat the insights/main events to yourself throughout the trip..its hard to bring a higher dimensional experience into lower dimensional mental representations, but repeating it to yourself throughout the experience builds the memory and helps bring it down into ordinary consciousness in stages
<Ringworm>hehehe, it's all fun and games till someone loses an "I"