Definitely figure out your niche and audience as even within the travel niche there's going to be specific keywords for styles of travel ie minimalist travel as well as people who focus on traveling to certain destinations. In general though destination tags ie where you're going, activity tags ie what your doing ex #hiking #scuba, etc. You can also do the type or style of travel you're doing ie #adventuretravel #budgettravel. You can also tag the type of accomodation your staying in ie #hostel the way your traveling ie #roadtrip or your niche of travel ie #familytravel. One last thing, for generic tags that apply to all travel things like #travelblogger or #travelgram.