Watch out for Araucaria's gems, usually on Saturdays. The Crossword Club publishes an excellent monthly magazine.
Sympathy is the software the pros use to construct and fill their grids.
Download a trial version for free. This is the site to get a copy of TEA, the most powerful tool to solve anagrams and complete words. The game has proven to be a big hit with young and old as well as with both crossword puzzle novices and aficionados. There are lots of on-line dictionaries . Here are a selection which I suggest you bookmark for use in an emergency.