Step 

suppose you need to develop a feature,when you finish the feature ,you need to release the jar to Nexus,and other projects will depend on your jar file.

1. cut a feature branch based on your develop branch, when you finish the feature,you need to run the UT
2. push your changes to feature branch, pull the code both on feature branch and develop branch. merge the develop branch code to your feature branch. mvn clean install passed
3. merge the feature branch to develop branch.  mvn clean install passed
4. cut a release branch base on develop branch, like release-3.0.0
5. pull the code and change the pom version to 3.0.0
6. add the <distributionManagement> configuration into pom.xml on  your project. add the <servers> configuration to your setting.xml if miss
7. push the code and mvn deploy
8. add a tag on release branch.
9. Check the jar on Nexus http://nexus.com/nexus/index.html

reference

distributionManagement:

<distributionManagement>
<!--This element is for releasing to nexus. 
The id element should match id in settings.xml file (xpath servers/server/id) which defines authentication credentials -->
<repository>
<id>release</id>
<name>releases</name>
<url>http://nexus.com/nexus/content/repositories/releases</url>
</repository>
<!-- Publish snapshots here -->
<snapshotRepository>
<uniqueVersion>false</uniqueVersion>
<id>snapshots</id>
<name>snapshots</name>
<url>http://nexus.com/nexus/content/repositories/snapshots</url>
</snapshotRepository>
</distributionManagement>

servers:

<servers>
<server> 
<id>release</id> 
<username>xxxx</username> 
<password>xxxxx</password> 
</server>
<server> 
<id>snapshots</id> 
<username>xxxx</username> 
<password>xxxx</password> 
</server>
</servers>