A) This is a broad question where you need to take into consideration many aspects such as depreciation, ROI return on investment, borrowings, etc.
There is good money to be made if you buy right and renovate within a budget that has an outcome of a fair sale price for the area.
It is important to take your time and research the area/market over a 3 month period to determine the lower and upper scale, average or medium sale prices for the area.
Following your research, you would want to invest in a property at the lower end (taking into consideration the number of bedrooms, bathrooms, garage space, outdoor area, etc.) and establish a realistic and achievable renovation budget that will improve the property, but not out price the market.
Renovating an old property could be a waste of money if the end result of the renovation (purchase price + budget - costs) is a sale price of $800k and the area sales are $500k-$700k, making a quick sale far harder to achieve.
Try to avoid properties requiring major structural changes and focus on cosmetic improvements if you are a first time renovator.