How do people get noticed so that they get into jobs like formula 1, world touring races and rally car racing?

May be...

by standing in bus stops???

WELL U GTA SHOW OFF AND DRESS LIKE A RACER. AND GET NOTICED IN STREET RACING

First of all you need a degree in engineering. The next step is often to be a racer yourself. Start with carts and you will get to know people. Because it is all about networking via that route.

Another route again starts with an engineering degree and an expertise in some useful discipline for the team. Then go to work for a manufacturer, engine builder, chassis builder. The way into these jobs is by getting to know who the companies are, then applying. Many times crew members work for these manufacturers and are assigned to a team.

Racing and crew experience helps again. Even if it is just for crewing for a local SCCA racer. It is best to work for a winner. While SCCA events will not get you noticed the experience will look good on a resume'.

You will find the racing community in North America remarkably accessable. If you go to races, buy pit/paddock passes and go during practice on Thursday and Friday. You may be able to talk to crew when things are not too intense. If everyone is working like mad to fix something it is not a good time to ask a question or intorduce yourself. If everyone is relaxed go ahead.

Don't grab for a top spot right away. Try for a spot in one of the support series first. Gain experience and work your way up.

Finally, appearence matters a lot. You will be a walking billboard. If you are not fit and presentable, you wont get a job. Eyeglasses are a no no, wear contacts so you can wear the shades.

If you want a mechanics job in F1, you will have to be an aircraft fitter as the technology in these cars derives from aviation.
A car fitter is not good enough for this.
The jobs are advertised in Motorsport magazine.