All newspapers, blogs and magazines (1 Across included!) have more compilers than they strictly need; there are lots of people who want to set crosswords, and only a limited number of spots! That said, we are always interested to hear from up-and-coming compilers; send your puzzle (ideally as two Word or PDF files, one with the blank puzzle and clues, and one with the completed solution and explanations) by email to the Editor. If sending puzzles, please bear the following in mind:
Different publications have different 'house styles' for what is allowed and what's verboten. The Times, for example, only allows names of people who are dead; most newspapers have sets of specific grids which must be used, and so on. Different publications have differing views on what is 'fair' in a clue - some will allow 'redhead' as a clue for 'r' while some argue that it should be "red's head" for the cryptic grammar to work properly. Sometimes, different setters within the same paper have different rules - for example, a couple of setters whose clues are known to be on the looser end of the Libertarian-Ximenean spectrum might be allowed 'winter' in a clue to mean 'w in ter' (ie 'twer'), but most wouldn't use that.
The 1 Across house style is pretty much 'anything goes', but that should be tempered with a cautious 'within reason'. If, when setting, you find yourself thinking 'I wonder if people will like [x] or hate it?' it's probably best to seriously consider replacing it with something else; if you decide not to, then don't go too overboard on oddities in the rest of the puzzle.
Now to the clues themselves. The editor isn't keen on clues with too many extraneous words in them. Occasionally a 'for', 'makes', 'becomes' etc. is necessary for the surface of a clue to make sense, but eliminating as many of those as possible makes for tighter clues. By way of example, a recent clue 'A question one had about water' (being AQUA) was changed during editing to 'A question on a liquid'. In the first version of the clue, 'had about' was superfluous - the 'had' looks like it could be an inclusion indicator, and the 'about' looks like it could be part of the definition (making the definition 'about water', perhaps), both of which muddy the understanding of the clue. In the edited version, there are no unnecessary words.
Finally, a note on the overall puzzle. 1 Across tends to publish puzzles with themes or interesting conceits. These have included alphabetical jigsaws (26 clues, each answer beginning with a different letter of the alphabet; answers must be fitted into the grid jigsaw-wises, wherever they will go; ideally clues will be ten-syllable rhyming couplets), perimetrical jigsaws (again, clues should be fitted in jigsaw-wise; the perimeter spells a message), barred puzzles with themes or constraints, circular puzzles on a theme, and so on. One thing to note on thems where 'x answers are of a kind' is that it makes for a much more satisfying solve where, when the solver has worked out the theme, you have to work to get the rest of the answers, rather than just write them in. (By way of example, in the early days of setting, Soup (the current Editor) wrote a puzzle whose answers included MONTY, PYTHON, FLYING, CIRCUS, and the names of the six actors within it; because of how they were referenced in the puzzle, once you'd got any of the words, it was easy to see what the theme was, and you could pretty much write in all the other nine answers, so the joy of the theme was lost.)
If it's your first time submitting puzzles to a magazine or newspaper, then the final piece of advice I'd give is to give your puzzles to a few friends who like solving crosswords, and get them to give them a try, ideally without you watching over their shoulder and giving hints. Get them to note down clues which they thought were a bit iffy, as well as clues which they really liked, and act on their feedback to improve the puzzle. There's always, always another way of clueing a particular word, so if there's something which doesn't go down well, keep working at it till you're really happy!