Now, that's a big question! The easy bit to answer is that, yes, you do plan a border with tall things at back and lower to the front, if it backs on to a fence or wall.
There will certainly be lots of help here with the rest of the question if you can tell us how wide the border is, how much sun it gets, what the soil is like and also the kind of border you would like - eg just flowers or a mix of flowers with shrubs? It's fun planning a new border.
My best advice for the moment is to look around nearby gardens and see what's growing well and have a look at what's on offer in the local garden centres to get a few ideas. Enjoy!
And welcome to GoY!

I'd echo Ojibway's response - length and depth of border, and whether it faces east or north or whatever, or, at the very least, whether it gets sun or not, and how much sun it gets. These factors are important when considering what to plant.

if i was you id look what the locals are growing for a start . then think what you actualy want long term and or short term from your garden . have you got children,grandchildren,dogs,cats . do you want a water feacture . these are all things best thaught about and sorted out now while you have a bare canvas . does your garden slope . which way does it slope . do you want modern,somewear to sit a pagoda . as said lots to think about . id get your self a scrap book if you like and go and vissit plenty of gardens,garden centres and look on this site to see what you like or dont like . do you want it user friendly ? lo0w maintanance or do you want to grow vedge . the world is your oyster as they say . a stitch in time saves nine . its worth thinking about before you jump in . i hope this helped .