How can we convince young people that pale skin is beautiful, to decrease skin cancer?

Sunscreen, check-up. Sunscreen and less intense sunlight exposure can really help lower risk of skin cancer. Frequent check-ups with your doctor/dermatologist also help greatly.
Education. It is a slow process, unfortunately. (along the lines of "how can we convince people to stop smoking? ") until it becomes hip to be pale, I recommend sunless tanning products, which can give the look without the aging and skin cancer effects.
Skin cancer. Show them pictures of skin cancer and sun damaged skin with wrinkles.

Related Questions

One of my moles recently started to bleed. Is that a sign of skin cancer? I'm a red head with very pale skin.

See your doctor. A bleeding mole is a warning sign. Please see your doctor to ascertain if the lesion needs to be removed for examination by a pathologist.
Could be. One of the classic signs of cancer is a change in mole or freckle. Certainly, you should have this checked out. You need to be ever vigilant with your complexion. Use an spf 15-30 skin creme, wear a hat, and avoid long exposures to sun. Good luck.
Possibly. This requires evaluation by a specialist. A biopsy might be required.
Could be. You should alert your dermatologist to any changes in your existing moles. It is time to see your dermatologist.

Having pale skin and a family history if melanoma what are some ways I can protect myself from getting the disease.

Protect your skin. Use sunscreen on skin that is exposed to sun. Wear a hat and long pants and sleeves when you can. Check your skin periodically for unusual moles; see your primary care or skin doctor for a skin check.
Melanoma Prevention. The most important way to protect yourself from melanoma is to avoid excess sun exposure and burns. Avoid peak hour exposure 12-2 pm, use a visor, sunglasses, and protective clothing, use a 30 spf sunscreen. With a family history of melanoma, I would recommend a preliminary total body check and mapping, with self-screening, and yearly follow-up.

I have a pale flat patch about 6mm come up on my cheek. Bit worried as my dad has had skin cancer. It's come in about the last 3 weeks?

Get it checked. It is unlikely that this is cancer but if you have a family history it is not unreasonable to have it examined.
See your derm. You should let your friendly dermatologist examine your new lesion.

Live in UK hardly get any sun n am really pale and spend lots of time indoors. If I go on holiday in hot climate n strong sun will I get skin cancer?

No cancer. If rarely exposed to sun, exposure can cause severe sun burn but not cancer. Long term exposure to the UV can enhabce potential for skin lesions such as squamous Ca and melanoma but not a primary cause. Should wear sun screen when getting excessive sun exposure.

Can you get skin cancer from a first degree sunburn when you have only had a few mild ones in the past? 18 yrs/ few freckles on nose&face/pale

Hard to predict. It is well known that sunburn and excess sun exposure increase the risk of skin cancer. He lifetime risk of skin cancer is 20% and it is estimated that by age 65, 40% of individuals will have acquired at least one lesion. Fortunately, most of these are not melanomas, which carry the worst prognosis. I recommend using sunscreen on a regular basis to minimize further risk and avoid tanning booths.
Unlikely. The risk of skin cancer goes up with the number of sunburns you have and the accumulated hours of sun exposure. Use sunscreen carefully from now on whenever you will have a prolonged sun exposure.
Cancer risks. Cancer comes from changes to the DNA- mutations, that can be caused by many things. Cancer begins only when enough changes have accrued to make cells that grow independently. But one can not tell right off if they have occurred. The more exposure the more risk, but single exposure does not mean zero risk, just lower. Take luck out of it and avoid risks.

Pale and went to desert without sunhat only sunscreen but still got blisters from sun will I get skin cancer. I've been burnt about 10-15x in life?

Increased risk. Exact prediction not possible. Only answer is that your risk is increased. Avoid tanning lamps. Protect from sunburn. Look for shade. Use a big hat and sunglasses. Protective clothing. Sunscreens. Learn what skin cancers look like. Take a baby aspirin daily: 81mg, not coated, reduces risk 10%. Niacin amide also is used to reduce risks.