Hydrogen vapor lock. I love it!

Can I use that?
It's actually nice to get the hang of being in/around rings. One of the visually-prettiest things in the game (imo) is when you're flying towards a ring to drop. It can be very pretty.
There are good tips here in the posts already made. Allow me to summarize:
In order to use your FSD (to enter supercruise or to perform a hyperspace jump):
Cargo hatch closed
Landing gear up
Hardpoints (weapons) stowed
Out of mass lock
Throttle up (to max generally)
Vectors aligned with ship's orientation (flying in the direction that you're pointing)
Additionally, for a hyperspace jump: pointed at the jump-target
Wow, that's a long list! What did I miss?
Enjoy learning, CMDR. Don't be afraid to ask questions here. Lots of CMDRs will try to assist you.