N.,
A budget is a must. It is so easy to over-purchase supplies and overspend because you haven't identified your financial ceiling for each project.
Check out some of the free classes offered by Home Depot and Lowe's. The websites should have a schedule posted and the classes will give you great hands on experience. There is also an expert there to help you with tricky spots and answer the inevitable questions. If you and your husband will be tackling these projects together, you should take the classes together too so you both know how the techniques should be applied.
Lastly, make sure you purchase good quality paint and painting tools. Talk to the representative in the stores and discuss the project, what you want the walls to look like, your budget, and the need for good quality supplies. They can help you find what you need and what you can afford.
Glidden paint is very good quality, but the colors are not always true. Sherwin-Williams paint is extremely good quality and out gasses less than other lower-quality paints. Higher quality paint is more expensive per can, but covers the wall better and requires fewer coats making it less expensive in the long run.
Painting can be fun, but make sure your first time is kid-free. Good luck!
C..