I agree with the above, but I also think that if you can find someone who has done it a bit, sitting down with him/her and working through it could be very helpful, especially if you have a themed puzzle, for which your choice of grid is probably somewhat restricted by the theme entries. I have not been at it that long, and I am already much better at seeing where there will be trouble and thinking about how to set up the grid. I still paint myself into a corner more often than I'd like, but I usually see it coming. I think that it's a bit like chess - the more practice you have, the farther ahead you can anticipate trouble.