New York Times: Behind London Tech Scene, a Government Push

In East London, many things were (not needed, implied by -ed of chang-ed) changed in (it might be better to say "over the course of", "in the past three years" or just "over three years" three years. East London,maybe a comma here in which there were few things,  try "few advancements,"? "few technologies,"? became the largest technology center in England. The British government has supported London to make it asinto a European tech hub. The Tech City Investment Organization helped the promotion of the tech hub. The process of visa issues try "visa issuing" or "issuing visas"... for entrepreneurs became easy and other obstacles decreased. Now the tech hub drew try "Then the tech hub drew"  attention of large American tech companies. Google had opened its office already in East London. However, the size of the British tech hub is still small, comparing"compared" or "when compared" with Silicon Valley. Also, there are other tech hubs in Europe. The amount of venture capital is smaller than Sweden or Israel. The success in London is ambiguous sincefor those reasons, such as small size of capital.
In the article, the tech hub in East London was covered. The world’s technology hub is Silicon Valley. There are many opportunities there(it helps to say where there are many opportunities) for entrepreneurs to grow up"grow" alone fits best "grow up" is like what children do!. Therefore, many entrepreneurs go to Silicon Valley with dream pick "with a dream" or "with dreams". The strategy of England targeted the advantage of Silicon Valley. It can generate the economic growth of England. The growth of the British tech hub would have a positive effect to"on" the world economy.

This is good work! Only a few little nits to pick.