My tips:
- Update your resume again. Have at least 2 other people proofread it and offer suggestions. Update it again. Move things around, lay it out so when you look at the full page it's pleasing to the eye and would make someone want to read it. Get it down to 2 pages if it's longer than that. Be terse in your verbiage. Basically you want to look at your resume and go 'damn that's a nice resume'. I can't count how many resumes I've thrown aside (as someone trying to hire) because they were 4 pages of useless fluff with zero formatting and my brain shut down after 10 seconds of trying to read them.
- I use craigslist, monster, and careerbuilder. They seemed to have the most relevant postings for me (I work in IT).
- Apply every single day/evening. Go to the library to job search after work if you'll get distracted at home and end up not getting around to it (I have to do this). The first day of searching will take a long time because you'll be considering/applying to things a week old, but if you do it every day you'll have much less work to do each time. But the main reason to search every day is...
- Apply immediately when you find something. I hear friends say 'I found an awesome-sounding job, I'm going to apply this weekend'. NO! Not this weekend, not even tomorrow morning. You apply now. Most jobs are available because someone is leaving, and the faster they get someone in there the better, so that job might not be there tomorrow. I've gotten at least one job the week it was posted because I applied same day, had at interview next day, second interview day after, then immediate offer. Move fast or someone else will, and they'll have the job.
- On job posting sites, I try to find out what the company is contact them directly if I can. I might email HR and say I applied online but also wanted to send along a copy of my resume for their convenience, or something. Especially if the online process is a stupid form and I didn't get to submit my actual resume. I just try to do something that makes me stand out, which is hard when everything is online and impersonal. I used to mail physical copies of my resume places after applying online, but in the IT industry I started to feel like that was making me stand out in a weird way rather than a good way. Though I did get an interview once for that specific reason. They were intrigued and wanted to meet me. Didn't get the job, but at least it got me in the door :-) Maybe that's something that would still be well-received in the engineering world.
- Put some effort into customizing the cover letter for the company/position. You don't have to write it from scratch each time, but include a line or two about the position and why you think you're a good fit. If you're applying via email, the email body is your cover letter, you don't have to attach one, that just makes the email body itself awkward.
Good luck!