Electronics tend to have tiny margins where as apparel can have huge ones.
However while electronics are often about selling what others make, market and has a likelihood of being major, clothing is extremely hit driven and very easy to miss. People already sell the "basics" at a great cost (think walmart) so most of the successes are from people making their own goods or finding what's on the edge of a trend.
And since you're selling what isn't yet known, you have to get people to latch on to it. A far cry from being the best price or most helpful retailer for the latest gadget.
I have always stayed far away from apparel when considering an ecommerce business. My main reluctance stems from how to handle returns. Who pays for the shipment back to you or your supplier? Who pays to ship it out again? If you pass those costs down to the customer, how do you charge them for it? Will the customer want to buy if they know it might cost them more to return something than to go to the local mall and buy something similar?
My wife is (ahem) an avid shopper. I bet you more than half of the clothes that she buys get returned because they don't fit right when she gets home (this is after she has tried them on in the fitting room at the store). She'd probably return 90% of the things she bought online (which she doesn't do, thank goodness).
Oh, and there are no margins at all on electronic goods. Your time and effort are worth more than the measly profts in that niche.
Oh yes. if you can source a supply chain which is reliable and prompt as well as securing payment upfront via Paypal/Worldpay/Credit card you have the beginnings of a very successful business.
Clothing will repeat faster than electrical and if you are shrewd enough you can have a very healthy margin.
The only sticking point is gaining awareness and site traffic so SEO is very important.