The best advice I have ever gotten in writing has always been 'write what you know'. I suggest if your interested in romance to find the romantic things in your life and use them. Use relationships, experiences, and interests you've had and create from them.
And secondly don't overthink it, you have to start at the basics. One plotline, two characters, and expand.
The third which I came up with (because I constantly did it myself) don't try to make it "like" any other novels you've read. And don't compare you're ideas if they seem to similar to another novel you know of.
Hope this helps.