Congratulations Loulou, good luck in your new home - this is an exciting time...
You ask a broad question, and I dont know if you have already chosen your property, but my advice to you as you start is:
1. location location location is absolutely true. Think about the person that will buy your flat after you - will you be able to re-sell it quickly? Dont buy the best flat on the block or the best house on the street. Have a GOOD look at your neighbours and walk teh streets or sit in your car at night if you dont know the area.
2. choosing the right mortagage is a bit complicated but there are loads of choices. Personally I think interest rates will be going up so if you are borrowing up to the hilt get a fixed rate. Regardless, get a mortgage that you can cope with in bad times as well as good. Draw up a monthly budget now including council tax, utilities etc so you know how much you can afford.
3. DONT USE CREDIT CARDS to kit out your new place. It will cost you an arm and a leg in interest and there is something fun about saving up for things, especially in your first place. I bought one piece of cutlery a week for I dont know how long before I got married. Beg, borrow (dont steal :-) )
4. Dont be afraid to take your Dad, or someone handy round with you on a second viewing. Nothing wrong with this, and he may spot flaws that a surveyor wont pick up. Dont rely on the surveyor to pick everything up, they dont even move furniture.
5. You say 'us'. make sure it is clear who is buying and make sure that matches up with a) who is paying and b) who is on the deeds
6. Are you thinking of starting a family soon? If so its all more complicated Im afraid! Will you have enough room and is it in a good school catchment area?
7. make a list of what you want and how important each item is
Have fun, search and search and search, and dont be afraid to bide your time until you fall in love