Checking in with a financial adviser is strongly recommended by experienced investors, but make sure you're speaking with a fee-only expert, who isn't receiving commissions for steering you into one investment over another. 

Once you find someone acting in your best interest, try to meet with them once a year or every two to three years. Find someone you can pay a flat fee for each visit. This will save you money in the long term.

There is no need to panic, even in times of big corrections in the market. With a diverse investment portfolio, you actually have an opportunity to make some extra money off of big swings in the markets by selling what has gone up in value and buying more of what's gone down.

Don't panic and sell everything just because the stock market crashes and you see other people panicking and getting rid of their stocks. That can do irreparable harm to your portfolio. Buying high and selling low is not a good way to make money.