I was vegan for 15 years, and plan to be again. There are reasons that I am not currently that are unimportant to this, but I will be vegan again when possible.
Biggest tip:
You are probably mentally used to 'protein' being the feature of a meal. Spaghetti and veggies may not do it for you, because there are no 'meatballs'... that sort of thing. It's completely mental, but to that end, ensure you find replacements [faux meats, etc] early on as you're adjusting. This will help you feel 'full' mentally.
Your body/taste will adjust faster than you expect. In a few months, anything that may taste odd to you now [be it rice/soy/almond milk, tofu, or fake meat, or whatever] will become the new normal soon enough. Once your body/mind shifts to this new normal, it will become -much- easier to stick to your diet, and will, in fact, become simple as it's normal.
If you seriously need to make an exception one day - say, a hamburger 6 months from now - don't beat yourself up over it. Have that burger, get rid of the urge, and go back to being vegan. Don't hang your entire veganism on some imaginary line where if you ever cross it you're like 'ok, welp, that's over now, burgers everyday!'. That said, try not to make these exceptions... the urge will eventually just go away as per the 'new normal' mentioned above. Find alternatives for the biggest urges... you can make some kickass egg sandwich alternatives, for example, with some tofu + salt + tumeric.
Plan for travel. Travel is always the hardest -- airports, truck stops, etc. Plan well, bring your food.
It's very easy to be super healthy and vegan. Make sure you get your various vitamins, sure, but don't fear the scare tactics some use against veganism. You won't turn into a meek nothing... watch your diet, stay on top of everything, and you can be as fit as fit can be.