I don't know really whether I have achieved anything in this regard... I often get comments from others that suggest I have, but I'm wary of putting too much store in them because vanity (resistance thereof) is one of the areas in which I'm well aware I need development. But... well, here are some of the things I do...
Firstly, I make sure I set aside time to meditate regularly. ENTP's can be such a whirlwind of activity, we get ourselves carried away and lose our centre I think, sometimes. An hour a week, perhaps, minimum, of just sitting in stillness and quiet to re-centre yourself can go a long way. It also provides the mental discipline to be able to STFU occasionally, something I think most of us could use lol
Secondly, I have a Rule that I live by. It's quite comprehensive, and it encompasses the underlying principles I value most and gives guidelines on applying them to the various aspects of my life. It acts as a sort of voluntary choke-chain, but the hand on the other end of the chain is my own, if you get me? Helps prevent me from wandering off so far on a tangent that I forget the point of why I went out in the first place. But it's flexible and open to different interpretations, so as not to make me feel stifled or really choked. It's got to be realistic, that's the key. Minimum requirements - then try to exceed them, better than unrealistic requirements and then the accompanying dismay when they're fallen short of.
Embrace your thirst for exploration and curiosity, but recognize when you're acting from this and when it's simple restlessness. Recognize the triggers for the latter, and circumvent them by giving plenty of nourishment to the former.
Planned upheavals are cool, too. You know how Ne primaries can sometimes sabotage our own lives by just getting so damned BORED that we're apt to just walk out of things, burn our bridges and stuff like that? Well, to avoid that, if I can sense it coming then I'll try to find an area of my life that I can utterly change the face of, totally upheave, to give myself the refreshment and challenge I need without burning bridges. Anything from simply redecorating with a totally new theme to moving house - just round the corner, giving away all my books and starting the collection from scratch (and relishing the "wtf are you DOING??" comments from others lol) or just randomly dyeing all my t-shirts so I become Red Man
Don't schedule yourself too tightly, or you'll feel suffocated, but just keep a calendar on the wall and pencil stuff in. Pencil in free days, too, and guard them jealously. Don't let "there's nothing on the calendar for that day" make you think it's a free for all to claim on your time. Set it aside for yourself to go and randomly explore somewhere or something (you know the old 'get in the car, flip a coin at each intersection' trick?), and consider that as much of a commitment as though it were one to someone else.
I might have more... must think about it some. Tell me what you make of it so far tho
edit - I might not be the best person to advise, in actual fact, since I think perhaps I might've embraced so much discipline in my life that this might be behind why I wind up doing 'little dangerous things' just to feel like I still have some risk and uncertainty in my life... driving without a seatbelt, impulsively deciding to refuse to say something diplomatically and telling it like it is with no punches pulled at the most inopportune of moments (ugh, all that Fe's been choking me!!)... cancelling something at the last minute, knowing it'll cause havoc, just to rebel against being needed/expected (all that Si!)... all kinds of stupid shit like that, which isn't very enlightened at all...