I've gone through this exercise about 2 yrs back. Here's my feedback/comments
1. Fix a budget - keep a 15% margin - STICK TO IT. Trust me there'd be so many temptations along the way which would end up doubling or even tripling your budget. Do not fall in for those temptations. The 15% margin is only for emergencies/contingencies - something doesn't fit and you'd have to get some other component, etc. kind of situations
2. The easiest thought for increasing the budget which you have to constantly avoid is - 'I am doing interiors for the first time and may not change it for a long time to come, let me just do this one extra thing'. Avoid taking this line of thought.
3. Tell your interior designer a budget which is 25% less than your actual budget. Trust me on this one !!!!
4. Focus on functionality and your comfort first. The looks of the whole thing would end up in the 'common' category sooner than you'd imagine.
5. Spend more on better quality than looks. It should last you 15 yrs - majority at least, unless you are someone who changes the interiors every 5 yrs !!
6. When you spend on lights - think real hard on how and when you are going to use them. The fancy lights looks superb but their usage depends on your comfort level. For example, I require a lot of white light in the house and am not comfortable with just a fancy lamp or two.
7. Spend most on kitchen - it is the most used place in the house and requires sturdy, waterproof materials.
8. Think of future expandability and have provisions for plug points, cable laying, etc. You may buy a lot of components in the future - plan for those (LCDs, home theatres, bigger fridge, bigger washing machine, etc.). More is better.
9. If its a new house, DO NOT put wood paneling on a complete wall without checking for leakages. In most of the new construction you'd find salt corrosion on walls show up after 4-5 months !!! Wood paneling these walls is a nightmare.
10. If you are going to have small kids around a lot, avoid sharp edges despite the fact that they look good and contemporary
11. The more you see the more confused you'll get. Have some kind of designs on you and ask your interior chap to work with those ideas. You don't want to copy something but create something unique.
12. Think of an 'Indian' house when you see concepts on websites and magazines before you plan to implement those ideas.
