Basically the investment and trading decisions are done with the help of two important tools.
1) Fundamental analysis
2) Technical analysis

Above mentioned two tools are widely used by investors and share traders but analyzing differs from traders to traders or from investor to investor.
First of all let’s see what these tools mean -

1) Fundamental Analysis
The name itself indicates that this analysis is totally based on companies’ fundamentals.
Basically the fundamental analysis is used to analyze the company fundamentals for mid term to long term investment or even some analyst use for short term investment especially during the announcement of quarterly results.
Like if the company is going to declare the good quarterly results then investors buy them before the results announcement, like one month before, and sell them as the price increases after the result announcement.

Following are the few fundamental parameters used to forecast and analyze the companies current and future growth. Like,

What is the company all about?
The analysis of quarterly, half yearly and annual financial reports.
What are the Company’s expansion and future plans?
How is the Management - like board of directors, chairman, CEO etc
The Companies involvement in foreign investment/collaboration or stake etc. and finally depending on these factors and many others, fundamental analysts have prepared certain fundamental ratios which will be used to forecast the company’s current valuation, future growth prospects, its debt and many more things.

Fundamental Ratios like -
PE (price to earning) ratio
EPS (earning per share) ratio
Book value
Working capital ratio
Return on equity ratio
Debt equity ratio

Based on these terms and other fundamentals terms, the analysts predict the movement of share prices whether it will be good investment or bad investment in coming future.
Always good fundamental analysis is utilized for long term period.
To understand more about these ratios and how to decide your good investments please go at How to analyze the stock or company

2) Technical Analysis
Technical analysis is second analysis tool for short term or for day trading.
As fundamental analysis is used for long term investments analysis likewise technical analysis is made for day trading or short term trading.
Technical analysis is nothing but study of charts made of four important numbers which are open price of the share, high, low and closing price of the share.
Technical analysis also make use of volumes, support and resistance levels, technical indicators and other parameters which are useful to analyze the share price movements in short term or in day trading.
There are several factors and terms used in Technical analysis are discussed at Learn Basics of Technical Analysis