I have an idea to improve products already on the market?

do I still need a patent? or do I contact the company - how do I get my idea heard legitimately

If your improvement is essentially making that product different, I think you might need a patent.

Be careful about sharing your idea/insight with too many people.

Be wary of the nay-sayers. They never do anything and seem to get off on discouraging other people.

You don't need to contact the company, at least not initially.
If your idea is to improve a kitchen faucet for example, there are hundreds of companies that make them.
I suggest you market your idea/improvement once you have it protected by law. Go to local colleges/grad schools, community groups, your church/temple etc, and show off your idea with a multimedia presentation.

Also remember---one hand washes the other---Tell everyone that you are building a business and that part of that is to build a network by promoting other businesses as well.

GO FOR IT!

You could contact the company with your idea. Since the product is already on the market, and is probably patented, it's unlikely that you could get a patent on that same product but with your improvement since that would probably infringe on their patent.

If you are expecting to be paid for your suggestion, that probably isn't going to happen.

I believe it's best to get a patent to protect yourself legally. I think it's pretty inexpensive and that you can do it online. An improvement is still a new item.
I think that patented ideas can even be bought by the companies online nowadays.
http://www.uspto.gov/ I suggest reading
It seems to me, it's best to approach the company after you have the patent. If I could avoid naming the existing product while creating the patent, I probably would.
I'm no expert... hope I've helped. Good luck!

Yes, by all means patent it first. Have you considered a business plan? Try your local unemployment office for advice on New Business courses that might be freely available via government approved agencies or your local college before contacting the company. Always remember the saying, Nothing Ventured - Nothing Gained, so GO FOR IT.