title_body: What's a good starting place to work on vocab?
upvoted_answer: If you're new to conlanging and want to start an entire language from scratch:  I would recommend reading The Language Construction Kit by Mark Rosenfelder.  It's a fun read and is very helpful to a new conlanger, and helps you know what to create for your purposes, how to do this, and gives you a good understanding of basic linguistics.
  
  For creating vocabularies from scratch:  A common practice is to begin with a list of roots and expand outwards, usually using some kind of derivational morphology.  The words you're going to want to begin with, besides words that come up in your grammar, which I think should be close to done by the time you start building a lexicon, are the basic concepts.  Things like man, tree, water, eat, do, green.  One famous example of such a list is the Swadesh list.  The way I made my vocab for my first language, Simean, was by coming up with roots for the concepts on this list and using morphological rules to expand that list.
  
  Another alternative, though one I don't personally use, is to simply translate things and make up the necessary words as you go along.  Even so, I'd start with the Swadesh list to get a good grounding in terms of what your language feels, looks, and sounds like.