With a 30 year time horizon trying to time purchases doesn't seem to be necessary in my book.  You need a bit of everything and if your in an IRA or other tax deferred situation you can use dividend reinvestment plans to keep the cash at work.

I would get several stocks now:  PG, JNJ, C, BAC, COP, XOM, CL, BRKB, GS.  I would also get some aggressive Vanguard Fund to cover the wilder side of the market for expert investment management which can turn on a dime, e.g. Primecap, etc.  You can add specialized funds in time.

I would leave about 10-15% in cash to take advantage of something which might pop up. 

I would advise reading Jonathan Clements articles regularly.  He appears weekly in the WSJ and on Sunday's in many local papers.  I don't think you need a subscription to read his articles (and prior ones) on the web.

You might also try to join a local investment club.  The best ones have older members and have been around more than 10 years.  Ask your neighbors for leads to the clubs.