You could have some issues with Harmony project if you try to help us with improving Ethereum client or just want to work with your own fork. Most common troubleshooting cases are below.

I am not able to debug project in IntelliJ IDEA

If you create project "Run/Debug configuration" with IDEA, your debug is not working sometimes. You could solve it by creating Application configuration with following settings:
Main class: com.ethercamp.harmony.Application
VM options: check what options are added in gradle config, it should be something like -server -Xss2M -XX:+UseCompressedOops -XX:+HeapDumpOnOutOfMemoryError -XX:-OmitStackTraceInFastThrow -Dethereumj.conf.res=private.conf -Ddatabase.name=database-private -DnetworkProfile=private -Xmx3500M
Everything else by default.

I couldn't configure Lombok in IntelliJ IDEA

Just follow this steps:
Go to Preferences -> Plugins:
Install Lombok Plugin

Next you should activate following settings for the current project:

Editor -> Inspection:
Check "Lombok annotations inspection"

Other Settings -> Lombok plugin:
Check "Enable Lombok plugin for this project..." and make sure all lombok annotations are activated