DO: Pick a certain coin/note and learn everything you can about it. By doing this it will be tougher to be taken advantage of and easier to identify certain aspects others may not see as easily.
DON'T: Think you are the professional, others will always have more information than you and can help out in a lot of situations.
DO: Set a budget and keep to it. Do what others have suggested by buying supplies and books as well.
DON'T: Buy the cheapest supplies for higher coins and expensive supplies for cheap coins. Along with the coins you buy there is a happy medium for the supplies you buy and not every coin needs a holder.
DO: Look at a variety of different coins/notes and buy some now and then to slowly add to your collection and knowledge.
DON'T: Buy the first thing you see and for the price it is listed at, most likely it is overpriced and set out for someone to make an impulse buy without thinking.
DO: Look at the Internet and online stores for coins and supplies, there are a ton of places to buy from and you can easily add to your collection.
DON'T: Buy without doing research again. This site is a great asset and has many helpful links of where to go and who not to buy from.
DO: Use
ebay to buy cheaper coins, fillers, a new piece or a great bargain. By watching the bidding and timing you can pick up some great deals and can get something better than you were hoping on.
DON'T: Buy a slabbed coin that is NOT one of the major companies, most of the slabbed stuff out there is by people in their basement using names, packaging and colors to look like PCGS and others. If these people were so good at grading they would work for one of these companies and not trying to pass off eye appeal for MS70, which reminds me, NO ONE has every coin for sale at MS70, this should be the first flag. Also check feedback, what they have bought, items they are selling and especially the shipping and insurance because if they do not insure then it also shows they know nothing about coins and don't care if you ever get it. Someone that takes the hobby seriously will do everything in their power to wrap, package and insure a piece to make sure you receive it.
DO: Have fun.