To begin with, something that you should do right away is to set a budget for your home improvement projects. This is something that I have seen many people avoid. They think that setting a budget is not important and they could not be more wrong. So make sure to talk to your partner and set a budget that you can afford.
What you should not do, is go over your budget. No matter what. I know that a lot of people will say to themselves, whats an extra hundred dollars, etc. But no, that is not the correct way of thinking. You need to see what part of your income you can put towards the project and stick to it.
Moreover, something that you should do is to ask for expert advice. Advice is free and there are a lot of people out there that will get you advice. So before you make a purchase, make sure to do your own research on the internet. There are many video sites, like youtube.com that have a lot of how-to videos. These videos can be very important in you finishing your job.
What you should not do is, not have a plan and try to wing it. That is not the correct way of doing things in any way. So make sure to have a budget and a plan and improve your home for the better!