My basic setup of a gulpfile.js.

gistfile1.js

var gulp = require( 'gulp' ),
		less = require( 'gulp-less' ),
		autoprefixer = require( 'gulp-autoprefixer' ),
		minifycss = require( 'gulp-minify-css' ),
		jshint = require( 'gulp-jshint' ),
		uglify = require( 'gulp-uglify' ),
		imagemin = require( 'gulp-imagemin' ),
		rename = require( 'gulp-rename' ),
		clean = require( 'gulp-clean' ),
		concat = require( 'gulp-concat' ),
		notify = require( 'gulp-notify' ),
		cache = require( 'gulp-cache' ),
		header = require( 'gulp-header' ),
		footer = require( 'gulp-footer' );

// styles task
gulp.task( 'styles', function() {
	return gulp.src( 'src/styles/main.less' )
		.pipe( less({ paths: ['src/styles/'] }) )
		.pipe( autoprefixer( 'last 2 version', 'safari 5', 'ie 8', 'ie 9', 'opera 12.1', 'ios 6', 'android 4' ) )
		.pipe( gulp.dest( 'dist/assets/css' ) )
		.pipe( rename({ suffix: '.min' }) )
		.pipe( minifycss() )
		.pipe( gulp.dest( 'dist/assets/css' ) )
		.pipe( notify({ message: 'Styles task complete' }) );
} );

// scripts task
gulp.task( 'scripts', function() {

	var customHeader = [
		'(function ( $ ) {',
		'"use strict";',
		'',
		'	$(function () {',
		''].join('\n');

	var customFooter = [
		'',
		'	});',
		'',
		'}(jQuery));'].join('\n');

	return gulp.src( 'src/scripts/**/*.js' )
		.pipe( jshint( '.jshintrc' ) )
		.pipe( jshint.reporter( 'default' ) )
		.pipe( concat( 'main.js' ) )
		.pipe( header( customHeader ) )
		.pipe( footer( customFooter ) )
		.pipe( gulp.dest( 'dist/assets/js' ) )
		.pipe( rename({ suffix: '.min' }) )
		.pipe( uglify() )
		.pipe( gulp.dest( 'dist/assets/js' ) )
		.pipe( notify({ message: 'Scripts task complete' }) );
} );

// images task
gulp.task( 'images', function() {
	return gulp.src( 'src/images/**/*' )
		.pipe( cache( imagemin({ optimizationLevel: 5, progressive: true, interlaced: true }) ) )
		.pipe( gulp.dest( 'dist/assets/img' ) )
		.pipe( notify({ message: 'Images task complete' } ) );
} );

// clean files and folders
gulp.task( 'clean', function() {
	return gulp.src( ['dist/assets/css', 'dist/assets/js', 'dist/assets/img'], {read: false} )
		.pipe( clean() );
});

// default task
gulp.task( 'default', ['clean'], function() {
		gulp.run( 'styles', 'scripts', 'images' );
} );

// watch task
gulp.task('watch', function() {

	// Watch .less files
	gulp.watch('src/styles/**/*.less', function(event) {
		console.log('File ' + event.path + ' was ' + event.type + ', running tasks...');
		gulp.run('styles');
	});

	// Watch .js files
	gulp.watch('src/scripts/**/*.js', function(event) {
		console.log('File ' + event.path + ' was ' + event.type + ', running tasks...');
		gulp.run('scripts');
	});

	// Watch image files
	gulp.watch('src/images/**/*', function(event) {
		console.log('File ' + event.path + ' was ' + event.type + ', running tasks...');
		gulp.run('images');
	});

});