It really will take longer and cost more than you expect. Don't fool yourself into thinking otherwise!
Recycle.. recycle.. recycle.
Do a cost benefit analysis when you're deciding whether to learn a new skill or hire out. In fact, this may not be the time to learn a new skill! Let me rephrase, you need to have a really good handle on your skill level. It depends too, on the level of renovation you are undertaking; if you're redoing a second bathroom—take your time and learn how to tile. If you've just gutted an entire house and don't want to live with your in-laws for the next five years, you may want to hire out for any tasks with which you don't have some experience and/or expertise.
You can save a lot of money by doing almost all of the work and having a professional finish up. However, you'll have to find someone who is comfortable with this proposition.
Check your area for a centre that accepts donations of building materials and resell it to others. Since we were designing our own plan we can save ourselves a good bit of $$.
You'll save time and money if you paint your house one color. Yeah, I know, pretty boring! But keep in mind that it's a lot easier to keep going with a nice cream color in every room than to change colors repeatedly. However, if you'd rather go with different colors—check out your paint supplier's returned. These are custom mixed colors that have been returned to the store. You may not find anything that you like, but if you do, you'll pay half as much for the "oops" paint.
Have you ever seen the notation "low hide" on a paint sample and not understood what it meant? You'll find this on dark yellow, orange, and red colors. Quite literally, it means that the paint does a rotten job of covering the walls. Expect to apply 5-6 coats before you have a solid color. Do yourselves a favor and splurge on tinted primer; this will give you a head start and reduce the number of coats needed!
Did I mention it will take longer and be more expensive than you planned for?
No matter the scope of your project, make sure your relationships can withstand the project! Where will you live while the renovation is underway? If you bunk with your parents or in-laws, be careful of your relationships. It's tough to live with anyone, but the stress of a big project like this and the inability to "get away from each other" will make it particularly challenging. If you're going to live in the house while renovating, think three times.