The past few months have changed me mentally and physically, generally just made me happier in a lot of ways.
1. Always do something, never rest until your ready for sleep. This way, you feel more accomplished and not in a mood of "Damn, wish I did that today".
2. Keep yourself up-to-date, I'm an avid RSS feed lover, I have it covering my desktop and FireFox. I own an iPod Touch, and I use the WiFi function ALL the time, just to keep myself in the knowledge. I wake up at 7am, go to my local shop and buy 3 of the most important newspapers (The Guardian, The Times and The Sun (The Sun, I read this because I enjoy gossip)).
3. Live hard, die young. Really, I live like this all the time. I smoke, I do the occasional spliff and I enjoy going into mosh-fights. It keeps me invigorated and moving. I want to travel the world, see everything and take photos of my life so I can look back when I'm 30 or something and think "Yeah, I did that!". What's stopping you from saving up a few grand over a few years and travelling the world, the only real thing is to share the experience with someone (Luckily I have a friend that likes this lifestyle).
4. Be happy! Smile, be vibrant and jolly. Not to the point of getting on peoples nerves, but just smile and listen to people. Laugh at jokes that you would'nt normally.
5. Have kids, share the knowledge from yourself unto them. I'd love to have 2 kids, look after and take care of. It may be weird going from "Live hard, die young", but if you live it like that you wont look back and wish you'd of done it.
6. Give your wife/husband the respect they need, give them space, give them love, give them comfort and share everything with them. Don't argue with them, just nod and accept their view. Ofcourse the odd rant with them is healthy and gets things off your chest but keep it respectful.
7. Learn everything, but don't be a smart-alek. I enjoy reading the latest book, or unravelling mysteries and then be fooled right at the end. Stimulating the mind with new things, such as a programming language, or how to build a vehicle, the best sleeping pattern etc. I'm 18 and I'm pretty full up with knowledge but I know there is so much more out there. I did crap at school, but that was because I was living life. I enjoy taking time out to learn things that I felt I should of learnt at school or wish they'd of taught it there. Things like how the world evolves, etc.
A lot of contradiction, but it's really what I want in my future life. Just enjoy it, don't slow down and share your experiences.