assuming, you are NOT doing this as a primary source of income, in general, if you are buying and selling properties, expenses are going to taken against each individual property on a property by property basis. Therefore, directly-related cost such as mileage, meals, broker fees, etc as part of the buying and/or selling process can be taken. However, if you buy a plane ticket to go look at a property, but do not buy it, then that travel expense is not deductable.
If you chose to use some other entity like and LLC or an S-Corp then things change a little bit; however, remember an LLC is a disregarded tax-entity (unless you chose otherwise) so in general the text above holds true. If you want more info this, I would encourage you to cruise over to the Legal/Asset Proetction forum as there are many, many old but very good post about different entity types and their associated tax treatments.
So, you mentioned a number of items like course, books, membership fees to clubs. In general, these are not going to be deductable (unless you choice to push the limits).
Real estate has a kind of special status in the eyes of the IRS and as such has special rules crafted around it. As a default, buying and selling real estate is going to be treated as investment income (and be dealt with on schedule D or E of 1040). This is not to say that REI can not be a Sch C (i.e. business) type activity, but you have a bit of an uphill battle and you needs be able to back it up and/or otherwise its going be treated as “passive income” and any loss can only be taken against passive income. See following link on page C-2, “Line G” instructions.
Here’s another useful links…
Happy Investing in '06 ;D