There are a lot of variables you can't control when applying for TPS, but control what you can. When able, start work on an engineering masters. If you have poor grades in some areas, considering attempting to retake those classes online. Apply early and apply often. Many, many people get in on their second or third try. Waivers for # of flight hours do get approved. So if you don't meet the minimums, don't let that discourage you from applying. Waivers for time in service are much more difficult to get approval for.