Some rewards credit cards come with fat sign-up bonuses. Here's what you should know before registering. Getty Images By Lisa Gerstner, Contributing Editor May 9, 2018From Kiplinger's Personal Finance When you choose a credit card, your primary focus may be on the rewards that you'll earn on everyday spending. But to sweeten the deal, card issuers are dangling big initial bonuses, too.SEE ALSO: The Best Rewards Credit Cards, 2018 Travel cards that recently offered generous bonuses include Chase Sapphire Preferred ($95 annual fee, waived the first year), with a bonus of 50,000 points (worth $625 in travel redemptions through the Chase Ultimate Rewards shopping portal) if you spend $4,000 on the card in the first three months of card membership; Capital One Venture ($95 annual fee, waived the first year), which hands out 50,000 miles (worth $500 in statement credits on travel purchases) if you spend $3,000 in the first three months; and Citi ThankYou Premier ($95 annual fee, waived the first year), which offers 50,000 points (worth $625 in travel bookings through Citi's ThankYou Travel Center) if you spend $4,000 in the first three months. Among premium travel cards, check out Chase Sapphire Reserve ($450 annual fee), with an initial bonus of 50,000 points (worth $750 in travel bookings through Chase) if you spend $4,000 in the first three months, and American Express's Platinum card ($550 annual fee), which offers 60,000 points (worth $600 in certain travel redemptions) if you spend $5,000 in the first three months. Business owners who travel frequently should consider the Chase Ink Business Preferred card ($95 annual fee). Its bonus was recently 80,000 points–worth $1,000 in travel redemptions through the Chase Ultimate Rewards shopping portal–if you spend $5,000 in the first three months. Try some tricks to nab a higher bonus than is advertised. If you're a customer of Chase's banking services and go to a branch to apply for a credit card, for example, you may be eligible for a larger bonus, says Vladislav Tyschuk, cofounder of RewardExpert, a website with information and tools for maximizing rewards. Another idea: If the issuer's website has a page on which you can check whether you prequalify for its cards, try filling out the form–you may be offered a bigger bonus, says Tyschuk. For example, with American Express go to their pre-qualified credit card offers page on their website. Don't overlook cards that offer a bonus after one year or provide annual bonuses, which could prove more valuable in the long run. The Discover It and Discover It Miles cards (no annual fee) both match the cash back or miles you've earned at the end of your first year of membership, doubling your rewards for that year. Barclays recently introduced the Arrival Premier World Elite Mastercard ($150 annual fee), which offers no initial bonus but an annual bonus of 25,000 miles if you spend at least $25,000 a year (or 15,000 miles if you spend $15,000). SEE ALSO: Will It Sink Your Credit Score?