Well, there are plenty of articles on the topic online. I would say if you are trying to do a decent research, you need to Google for it. Also, the information is straightforward to find.
Still, if you need it short, I would resume it in few points.
1. Stock Repurchase (or Stock Buy-Back), a standard method to boost the share price. The reason is that in a stock buy-back the demand for the stock increases and hence its price.
2. Raising Debt, for it can lower the overall risk of the firm provided that the business has not reached the point of financial distress yet.
3. Organisational Restructuring, after evaluating, valuing and prioritizing the primary assets of the company, of course.
4. Mergers & Acquisitions
5. Diversifying Portfolio
An additional strategy can be using a small percentage of net income as capital investments to other businesses.