Okay, I'm not a "professional designer", but I have to say that I'm kinda experienced, having made a couple pages I'm proud of.
So I may not know the ins and outs of this business, but I just look at it this way - what would you customers or people using this want? Do they want Times New Roman 404 text on a white background? Or do they want something sleek and simple?
Start off with this - find a…"sleek" font.
This is not sleek. It's default, and kinda boring.
…okay, I don't know what's so bad about it. But it's just not "special" and doesn't have THAT feel.
This is my personal favorite. Sans-serif fonts in general fall into this category.
This is for older computers - if you're a cutting-edge, high-res website, this is probably the worst thing you can do to your website. However, it's best to use if you know for sure that smaller, low-res monitors will browse your website most of the time.
This is a good example of a "sleek" serif font. I don't know why, but it just looks, I guess, manly?
Every font has its own feeling. Choose which one speaks to your website's goals the "best".
Then, move on to the boxes around it. Do you want it round, or do you want it straight corners?
Then the background. Search up on Google, and find some pictures. Make sure to keep down the website you took them from, because if not, you'll run into a lot of legal trouble. But besides that, what do you want to have on the background? If not to use them explicitly, at least to give you an idea of what you want.
Lastly, remember to update often. Every time you add a new line or text box, remember to check it out in the context of your website. That's why I like to work in a desktop app so much - you just need to click it once, and it refreshes for you. Although for a program, it's different, but still.
…that's about as much as I know.