Disclaimer: These tips are for the blog author, pls seek professional instruction as this sport may be dangerous!
It took me a while to figure out what helps me roll over an uphill, flat or downhill obstacle on a tough part of the trail where I could not before...
The answer is MOMENTUM!
Even with a very tiny and modest momentum one can roll over surprisingly difficult stuff. This can include an acceleration or more often simply NOT SLOWING DOWN in regards to the initial approach speed.