I am not an expert but have some suggestions.
First it depends on your budget but i will try to give you options.
1. I would say a dedicated macro lens or "magnification lenses" that you screw onto your excisting lens, the first much more expensive. For macro lenses I just love the 105mm Nikon but it is somewhat expensive. And all macro lenses are very sharp even used as normal photograpy lenses, they are though often a little slow to focus!
2. Try to find forums for photography and there is often a section for macro or flower photography, there you can lern alot. Depending on your experience, you may want to invest in a basic photo instruction book that describe photography from the basic.
3. YES, a good tripod is a very good investment if you would like to do macro photography! You can the n use a small aparature under low light with long shutter times.
I would suggest a tripod before a macro lens as it is essensial for good macro photograpy. For those screw on lenses I would say that the result depends on what optics they are added to and your lens is a consumer kit lens that is not optically that good.