There is an inverse relationship between reward and risk. But, a diversified portfolio, held over a long period of time, should net the kinds of returns you're seeking. What you are looking for is very reasonable.
My first piece of advice is to check out ETF's and funds at Vanguard (and TIAA-CREF, if you have access to it). Both have very low fees. Slaying the fee dragon right off the top helps get you over the hump.
Then, I would say, find investments that you're comfortable with and diversify. Read enough to balance your portfolio, but don't obsess over finding "the next great thing." Sure, we could probably all obsess and max out returns, but that comes at a price too (stress, time).
Your goal should be to put it on auto-pilot, then tweak as necessary (once a year or so).
If you're really troubled about going it alone find a fee only financial advisor. But, if they're only recommending funds they represent, tell them to take a hike.