How do you begin an investment portfolio?

For a total newbie, how should I begin? Do I etrade on my own or do I find a professional? Where do all the rich people get their trading advice?

The very first thing you should do is brush up on some basic terms and principles of investing ( such as stocks, bonds, mutual funds, buying on margin, short-selling, etc.) so you know what you're putting your money into, and not just following someone else's advice blindly.

The best thing you could do when setting up an investment portfolio is asking your self a few simple questions:
1.How much capital ("extra money") am I able to invest?
2. Am I looking for long-term or short-term growth in my investments (long-term usually gets you more money)?
3. How much risk am I actually willing to take (Though the higher the risk the greater the potential return)?
4. And remember to keep your portfolio as diversified as possible so if one stock is doing badly you'll have others that are performing well enough to cancel out your losses.

For someone new to investing, I would recommend going into mutual funds. These are really safe investment vehicles in which a professional "broker" manages all the buying and selling of stocks for a large group of investors. Your money is basically pooled together with other's and used by the mutual fund manager to buy large amounts of stocks off the market. You get a percentage of the profit depending on how much you put into the fund.

Most wealthy people use Hedge Funds which are basically like Mutual Funds, but A LOT RISKIER. The managers of Hedge Funds are always trying to "beat the market" by attempting to make money when the market is performing badly ("Bear Market") or when it is doing well ("Bull Market")

Investopedia.com is a great place to get started on learning about the stock market and other investment strategies. They even have a stock simulator where you can trade stocks using virtual money based on the real stock market's performance.

Hope that answered your question

This link will be good, I think :
http://www.investopedia.com/university/b...
Good Luck.

first thing you need to do is to invest your money in education. for example : courses, or books about investing.

before you risk any of your money, start reading. I would start with "One up on wall st" by peter lynch. Its very simple but important concepts. I would also start investing using Sharebuilder. You can automatically by stocks a little at a time and don't need a lot of money to start. It will also help you avoid mistakes that most new investors make like trading too often.

First you need a portfolio,go to Office Depot or Staples,something leather would be nice.As for investment ideas this link may help. http://charting-the-market.com/

I don't think you need a professional unless you have huge sums of money (they charge you a lot).
Better to subscribe to a good financial magazine like Kiplinger's or MONEY and/or Investing for Dummies. You will get the same advice for much less.
1.) Figure out what your goals are (investing for retirement, buying a house, etc. and set up an account accordingly. (I like TDAmeritrade but there are several good ones). Make sure they don't charge you a lot for trading unless again you have large sums of money - trading fees cut into your profits! Look for no maintenance or inactivity fees - you should not be forced to trade to save money.
2.) Figure out your risk tolerance. Individual stocks can fluctuate dramatically and minor announcements can have a deep impact on a stock. Never own less than 14 to 20 individual stocks and make sure they are in different sectors of the Market (like financial stocks, technology, natural resources, etc.). If you are uncomfortable with high risk look at diversified mutual funds. Again make sure you capture broad sections of the Market and don't buy funds owning only a certain segment of business. Mutuals also give you a great way of owning international stocks. (you should always have a certain exposure to international markets.
3.) Read and inform yourself regularly. Markets change, business changes, know what you own. Too much info can be confusing but it's not something that can be put on autopilot either. Again, pick up some literature like the ones I mentioned earlier and find what interests you.
4.) May the bulls run with you.