Fees to keep your eyes peeled for :

*administrative/reporting fees
*desk fees
*Markup on ECN fees
*Rounding to the nearest (tenth or cent) you won't see this until you actually understand your trading statement.
*training fee which also becomes "capital contribution"


Anyone care to add to the list.....

These fees are so important when you first start. If I wasn't sitting next to a trader who knit picked every single little fee I wouldn't have even picked up on most of them. I think the most important is picking the correct ECN destination to route your orders to and capturing the rebates. 

The only problem I have with always trying to capture a rebate is many missed trades. I missed many good trades trying to enter at the bid only to see it take off without me, and lost many a great profit trying to offer at the ask and not get hit and watch it quickly pull back. I guess knowing when to enter at the market or using a limit order and capturing the rebate comes with time and experience. I do for the most part try to add liquidity; however, if I feel the need to get out for whatever reason I will without worrying about trying to catch the rebate.

I believe a firm has to survive and there are fees here and there, however I do NOT believe in any fee for training. I have yet to come across anyone who is a successful trader who provides training. 99% who run the training programs never made as a trader and jumped into the (educational, training, mentoring) part of the biz. Don't pay for training ever!!!!