The online profile posted on dating web sites is essentially the 'marketing tool' that will be searched when a prospective date/mate is deciding whether to contact you or not! It is well worth the investment of thought and time.
First and foremost, one should not rush the posting of an online profile. I have dabbled in online dating a few times before and definitely had some good results as well as some interesting encounters! Misspelled words, incorrect grammar, etc. deter prospective dates and contacts who are forming their image of you and trying to decide to "wink," e-mail, or otherwise establish contact!
Therefore, answer all the requested questions and put some thought into your responses.
Secondly, be honest. If you meet someone and discover the bulk of their online profile was in fact false, or inaccurate it damages their reputation and wastes time. So be honest and truthful in your entire profile.
This brings me to my third key point . . be yourself! Be confident in who you are and your unique attributes.
Post a current of a picture of yourself so it is an accurate representation of what you look like when you meet in person. I have met many a person who I perceived to be younger, thinner, or have more hair given their 'online picture'. I didn't mind the mature, stockier, distinguished, balder person but began to question what else had they misrepresented. It damaged their overall credibility.
It's exhausting to try to keep up a façade or pretend to be someone you're not. When trying to stand out online, let your uniqueness shine through; it's what makes you you!
Be proud of what makes you unusual and put it out there. You will be thrilled to meet someone who shares that interest, or can appreciate that.
As it costs money to post an online profile, make the most of that investment of thought and time to create a unique profile.