I have my right nipple pierced, bloody hurt like hell as it was done, but that was nearly 10 tears ago now.
My GF has 6 or 7 tattoos, only one of which she regrets having had done. This was because the guy who did the tattoo was not skilled enough as an artist to realise her design correctly.
Perhaps a view to getting anything like that done is to spend alot of time thinking about the design/artwork to be tattooed, then find somewhere to actually have it inscribed into your skin- chat to the ppl working there and if you're not happy with what you see then find somewhere else. Also a rule of thumb is that the more expensive the tattooist, it's quite probable that they are justified in their skill to charge such amounts. A great tattooist should have a portfolio thing of previous works which should not include swallows tattooed on ppls necks or 'love/hate' on ppls knuckles! hehe.
Do think long and hard about the tatto itself and the person to tattoo you. Once it's done, it's done; so it has to be right first time.
As far as cleanliness is concerned- when I had my piercing done, both the piercing needle and the ring were made of surgical grade stainless steel and were taken from sealed and streralised packaging. If you don't see the guy take the needle out of a sealed package and wear sterile surgical gloves, then don't let him anywhere near you with it
Looking after you new piercing/tattoo after it has been done is as important as choosing where and what to have done. A large proportion of the horror stories about infections and such like are due to folk not looking after themselves properly.
With piercings of any sort they must be left alone (ie not moved about too much) and cleaned twice a day with salt water solution or tee tree oil or other recommended antiseptic treatment. They must be kept as clean and dry as possible and given a chance to heal propperly- in my case it took about 4-6 weeks for it to heal up fully. After this it does not mean you can forgett about cleaning the piercing! pay special attention to removing any crud that builds up where the steel enters the skin and in the course of normal daily washing make sure the piercing is soaked and is free to rotate without sticking or pain.
Tattoos will itch like hell- don't scratch it or you will bugger up the design, as part of the process is to allow the tattoo to scab over and seal the ink into the skin. Again, keep them clean and dry, and when the itching starts have a go with a gentle moistureiser cream (note: do NOT do this when the tattoo is still bloody, only after it has fully scabed over!). Expect about 4-6 weeks to heal fully.
With both tattoos and piercings expect there to be some bruising of the skin and swelling in or arround the affected area. This should become apparent after an hour or so and will probably last about a week. If you notice the pain or swelling grow and not lessen over or after the first week or two, then go see your doctor as you may have an infection. The worst thing to do is to leave it untreated if you think there is a problem.
If you choose your venue to have your tattoo/piercing done carefully and follow all the instructions about looking after your new tattoo/piercing, there should be no reason why you should have any problems whatsoever.