Momopi,
Diversification, and continued investments ( meaning don't try to time the market buy or sell) are time-proven ways of creating a good return. You probably already heard all the following from someone at some point, but it works:
a. make sure you have a 6 to 12 month of emergency fund that you can easily tap into. For this fund, I will just put in a money market fund like fidelity california AMT free money market fund", which is generating a 3.5% return withOUT fed and state income tax.
b. For additional savings (after tax saving or before tax ie 401K), you should diversify based on your age...For someone around 35, I will suggest:
50% large cap growth
15 % mid cap growth
10% small cap value, i.e. T. Rowe Price small cap
15% international , i.e. Fidelity Diversified international ( closed to new investor)
10% emerging markets, ie. T.Rowe Price emerging markets
This is a relatively aggressive diversification. You can turn down the aggresiveness by less international and emerging markets. Also, small caps has been doing really really well ( 20% / yr), it might be time for a plause.
c. lastly, you need to rebalace one or twice a year to make sure the diversification fits you need.
Check out the Money Mag"s top 70 mutual funds in every issue, they list some of the better funds out there. Also, I will only purchase funds that are rated a 4 star min by "morningstars"