My first suggestion is to, know yourself. Are you willing to read a book or two on investing? Is the thought of about 10 hours of homework a month working on your investments, more than you are willing to spend?
Investing, and learning the investment ropes, take some real time and effort. If you are willing to spend the time, there are many good references. I personally like, The Motley Fool:
http://www.fool.com/
But, if you are not willing to spend the time, or know that you just won't... a professional advisor may be a better choice for you. I believe the most important considerations for investing are to:
1. Decide to start, and do so early in life. Compounding interest is your friend!
2. Get rid of any high interest debt. Don't carry a balance on your credit cards! A car loan is acceptable, as long as it is at a decent rate. (For the most part, cars are not investments. To put it another way, most cars are really bad investments. They are almost guaranteed to decline in value. The less money you spend on them and maintenance, the better.)
3. A home can be an excellent investment... A bank will give you money to buy a home (They will not want to loan you money to invest without other capital.), the government will let you write off your property taxes and loan interest expense, and you get to live there! But, this is only one investment, and must be balanced with your other goals.
4. Put an amount into your investments each and every month. Pay this just like any other bill that must be paid.
5. Do your homework before investing. Know what the fees are for the investment. Know what the cost of getting out of the investment is. Realize what your tolerance for risk is, and make decisions consistent with that.
I would suggest to anyone interested in a professional advisor, to look for someone that has been in the business for at least 10 years. (Why be the newbie's learning ground?) I also like the idea of an advisor that charges a fixed yearly fee to manage your investments. I would suggest interviewing several. They should want to get an idea of how much you are willing to invest each month, and what assets/investments you currently have. They should be discussing setting up some sort of plan, where they look at what your investments are likely to make each year, and what money you will have to support yourself come retirement.
Advisors are also available that make money based on the transactions that occur on your account, and the sales they make. This can be a decent approach, but be aware they are making money on the products they are selling you.
My biggest advice is to start now. It is never too early to start. Make it a priority, and don't procrastinate.