Build stuff that is already out there - competition is fine in any marketplace if there are enough consumers for the product. Create a copy of software that is already performing well, tweak a bit of it to give it your own flavour - copying something that already exists will give you the chops to pull off something unique when the inspiration hits you. Kind of like learning to play music - learn some basics, copy the classics/standards in your style, improvise a bit on the classics and eventually, write your own tune.

If you can find it, look up jgc's talk at the last HN London meetup - he gave a talk on "ideas" it was good.